[thirdparty/gcc.git] / libstdc++-v3 / ChangeLog

2023-05-03  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/105844
        * include/std/numeric (lcm): Ensure out-of-range result is
        detected in constant evaluation.
        * testsuite/26_numerics/lcm/105844.cc: Adjust dg-error string.

2023-05-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-06-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/105844
        * include/experimental/numeric (experimental::gcd): Simplify
        assertions. Use __abs_r instead of __absu.
        (experimental::lcm): Likewise. Remove use of __detail::__lcm so
        overflow can be detected.
        * include/std/numeric (__detail::__absu): Rename to __abs_r and
        change to allow signed result type, so overflow can be detected.
        (__detail::__lcm): Remove.
        (gcd): Simplify assertions. Use __abs_r instead of __absu.
        (lcm): Likewise. Remove use of __detail::__lcm so overflow can
        be detected.
        * testsuite/26_numerics/gcd/gcd_neg.cc: Adjust dg-error lines.
        * testsuite/26_numerics/lcm/lcm_neg.cc: Likewise.
        * testsuite/26_numerics/gcd/105844.cc: New test.
        * testsuite/26_numerics/lcm/105844.cc: New test.

2023-05-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2023-04-28  Jonathan Wakely  <jwakely@redhat.com>

        * doc/doxygen/user.cfg.in (STRIP_FROM_PATH): Remove prefixes
        from header paths.

2023-04-28  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-24  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/67791
        * src/c++11/thread.cc (thread::_M_start_thread(_State_ptr, void (*)())):
        Check that gthreads is available before calling __gthread_create.

2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2023-04-04  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/extensions.xml: Remove std::bad_exception from
        example program.
        * doc/html/manual/ext_demangling.html: Regenerate.

2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        * doc/doxygen/user.cfg.in (SOURCE_BROWSER): Only set to YES for
        HTML docs.
        * include/bits/gslice_array.h (_DEFINE_VALARRAY_OPERATOR): Omit
        from doxygen docs.
        * include/bits/indirect_array.h (_DEFINE_VALARRAY_OPERATOR):
        Likewise.
        * include/bits/mask_array.h (_DEFINE_VALARRAY_OPERATOR):
        Likewise.
        * include/bits/slice_array.h (_DEFINE_VALARRAY_OPERATOR):
        Likewise.
        * include/std/valarray (_DEFINE_VALARRAY_UNARY_OPERATOR)
        (_DEFINE_VALARRAY_AUGMENTED_ASSIGNMENT)
        (_DEFINE_VALARRAY_EXPR_AUGMENTED_ASSIGNMENT)
        (_DEFINE_BINARY_OPERATOR): Likewise.

2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-10-28  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/fs_path.h (path::filename()): Fix dangling
        reference.

2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/109064
        * python/libstdcxx/v6/xmethods.py (SharedPtrUseCountWorker):
        Remove self-recursion in __init__. Add missing _supports.
        * testsuite/libstdc++-xmethods/shared_ptr.cc: Check use_count()
        and unique().

2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2023-02-28  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/108952
        * include/std/memory (uses_allocator_construction_args):
        Implement LWG 3527.
        * testsuite/20_util/pair/astuple/get-2.cc: New test.
        * testsuite/20_util/scoped_allocator/108952.cc: New test.
        * testsuite/20_util/uses_allocator/lwg3527.cc: New test.

2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2023-02-16  Jonathan Wakely  <jwakely@redhat.com>

        * include/experimental/optional: Fix header name in comment.

2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-07-20  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100823
        * include/bits/stl_iterator.h (common_iterator): Define move
        constructor and move assignment operator.
        (common_iterator::_M_assign): New function implementing
        assignment.
        (common_iterator::operator=): Use _M_assign.
        (common_iterator::_S_valueless): New constant.
        * testsuite/24_iterators/common_iterator/100823.cc: New test.

2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-07-20  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_iterator.h (common_iterator): Fix incorrect
        uses of is_nothrow_assignable_v. Fix inconsistent constraints on
        friend declaration. Do not move argument in copy constructor.
        * testsuite/24_iterators/common_iterator/1.cc: Check for
        noexcept constructibnle/assignable.

2023-04-27  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-11-23  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/107814
        * testsuite/experimental/filesystem/iterators/error_reporting.cc:
        Use a static buffer with space after it.

2023-03-16  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2023-02-02  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/108636
        * include/bits/fs_path.h (path::path(string_view, _Type))
        (path::_Cmpt::_Cmpt(string_view, _Type, size_t)): Move inline
        definitions to ...
        * src/c++17/fs_path.cc: ... here.
        * testsuite/27_io/filesystem/path/108636.cc: New test.

2022-11-08  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-11-08  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/authors.xml: Remove empty author element.
        * doc/xml/manual/spine.xml: Likewise.
        * doc/html/*: Regenerate.

2022-08-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-31  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/98421
        * include/std/span (span(Iter, size_type), span(Iter, Iter)):
        Add valid range checks.
        * testsuite/23_containers/span/cons_1_assert_neg.cc: New test.
        * testsuite/23_containers/span/cons_2_assert_neg.cc: New test.

2022-08-03  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/list.tcc (list::merge) [!USE_CXX11_ABI]: Remove
        call to size() and try-catch block.

2022-08-03  Tim Adye  <Tim.Adye@cern.ch>

        Backported from master:
        2021-06-04  Tim Adye  <Tim.Adye@cern.ch>

        * include/std/any (any::_Manager::_S_access): New static
        function to access the contained value.
        (any::emplace, __any_caster): Use _S_access member of the
        manager type.

2022-08-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-15  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (subrange(i, s, n)): Remove assertion.
        * testsuite/std/ranges/subrange/constexpr.cc: New test.

2022-08-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100748
        PR libstdc++/103133
        * config/os/gnu-linux/os_defines.h (_GLIBCXX_GTHREAD_USE_WEAK):
        Define for glibc 2.34 and later.

2022-07-23  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-07-01  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/106162
        * include/Makefile.am (largefile-config.h): Add
        stamp-${host_alias} prerequisite.
        * include/Makefile.in: Regenerate.

2022-07-23  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-05  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/range_access.h (begin(valarray), end(valarray)):
        Add noexcept.

2022-07-22  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2022-07-22  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/106320
        * include/std/ranges (single_view): Relax constraints on
        default constructor so as to preserve pre-P2325R3 behavior.
        (filter_view): Likewise.
        (transform_view): Likewise.
        (take_while_view): Likewise.
        (drop_while_view): Likewise.
        * testsuite/std/ranges/adaptors/join.cc (test13): New test.
        * testsuite/std/ranges/p2325.cc: Fix S to be only non default
        constructible and not also non copy constructible.  XFAIL the
        tests that verify a non default constructible functor makes a
        view non default constructible (lines 94, 97 and 98).  XFAIL
        the test that effectively verifies a non default constructible
        element type makes single_view non default constructible (line
        114).

2022-06-28  Release Manager

        * GCC 10.4.0 released.

2022-06-15  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-06-13  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/atomic (__atomic_val_t): Use __type_identity_t
        instead of atomic<T>::value_type, as per LWG 3220.
        * testsuite/29_atomics/atomic/lwg3220.cc: New test.

2022-06-15  Mark Mentovai  <mark@mentovai.com>

        Backported from master:
        2022-06-13  Mark Mentovai  <mark@mentovai.com>

        * include/experimental/bits/fs_path.h (__detail::__null_terminated):
        Rename to __nul_terminated to avoid colliding with a macro in
        Apple's SDK.

2022-06-15  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-05-06  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/104731
        * testsuite/27_io/filesystem/iterators/error_reporting.cc:
        Use a trailing char array as storage for dirent::d_name.

2022-06-15  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-02-02  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/27_io/filesystem/iterators/error_reporting.cc: Use
        autoconf macro to check whether d_type is present.
        * testsuite/experimental/filesystem/iterators/error_reporting.cc:
        Likewise.

2022-06-15  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-02-01  Jonathan Wakely  <jwakely@redhat.com>

        * src/c++17/fs_dir.cc (recursive_directory_iterator::increment):
        Reset state to past-the-end iterator on error.
        (fs::recursive_directory_iterator::pop(error_code&)): Likewise.
        (fs::recursive_directory_iterator::pop()): Check _M_dirs before
        it might get reset.
        * src/filesystem/dir.cc (recursive_directory_iterator): Likewise,
        for the TS implementation.
        * testsuite/27_io/filesystem/iterators/error_reporting.cc: New test.
        * testsuite/experimental/filesystem/iterators/error_reporting.cc: New test.

2022-06-15  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/23_containers/map/allocator/move_cons.cc: New test.
        * testsuite/23_containers/multimap/allocator/move_cons.cc: New test.
        * testsuite/23_containers/multiset/allocator/move_cons.cc: New test.
        * testsuite/23_containers/set/allocator/move_cons.cc: New test.

2022-06-15  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-12-01  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103501
        * include/bits/stl_tree.h (_Rb_tree(_Rb_tree&&, false_type)):
        Clear container if elements have been moved-from.
        * testsuite/23_containers/multiset/allocator/103501.cc: New test.
        * testsuite/23_containers/set/allocator/103501.cc: New test.

2022-06-14  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97944
        * testsuite/30_threads/jthread/95989.cc: Mark XFAIL.

2022-06-14  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-24  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/30_threads/jthread/95989.cc: Run all three test
        functions, not just the first one twice.

2022-06-14  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-04-28  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99290
        * src/c++17/fs_ops.cc (fs::copy): Pass error_code to
        directory_iterator constructor, and check on each iteration.
        * src/filesystem/ops.cc (fs::copy): Likewise.
        * testsuite/27_io/filesystem/operations/copy.cc: Check for
        errors during recursion.
        * testsuite/experimental/filesystem/operations/copy.cc:
        Likewise.

2022-06-14  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-05  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/lib/gdb-test.exp: Add target selector support to the
        dg-final directives.
        * testsuite/libstdc++-prettyprinters/80276.cc: Add xfail for
        C++20.
        * testsuite/libstdc++-prettyprinters/libfundts.cc: Likewise.
        * testsuite/libstdc++-prettyprinters/prettyprinters.exp: Tweak
        comment.

2022-06-10  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-06-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/105915
        * include/experimental/bits/fs_path.h (path::begin, path::end):
        Remove noexcept from declarations.

2022-05-31  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-07-16  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/103904
        PR libstdc++/101231
        * include/std/ranges (_CachedPosition::_M_get): For non-forward
        ranges, just call __builtin_unreachable.
        * testsuite/std/ranges/istream_view.cc (test05): New test.

2022-05-31  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-06-18  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/103904
        * include/bits/iterator_concepts.h (weakly_incrementable): Remove
        default_initializable requirement.
        * include/bits/stl_iterator.h (common_iterator): Constrain the
        default ctor.
        (counted_iterator): Likewise.
        * include/std/ranges (ranges::view): Remove default_initializable
        requirement.
        (subrange): Constrain the default ctor.
        (__detail::__box::operator=): Handle self-assignment.
        (single_view): Constraint the default ctor.
        (iota_view): Relax semiregular constraint to copyable.
        Constrain the default ctor.
        (iota_view::_Iterator): Constraint the default ctor.
        (filter_view): Likewise.
        (filter_view::_Iterator): Likewise.
        (transform_view): Likewise.
        (transform_view::_Iterator): Likewise.
        (take_view): Likewise.
        (take_view::_Iterator): Likewise.
        (take_while_view): Likewise.
        (take_while_view::_Iterator): Likewise.
        (drop_while_view): Likewise.
        (drop_while_view::_Iterator): Likewise.
        (join_view): Likewise.
        (split_view): Constrain the default ctor.
        (common_view): Likewise.
        (reverse_view): Likewise.
        (elements_view): Likewise.
        (elements_view::_Iterator): Likewise.
        * include/std/span (enable_view<span<_ElementType, _Extent>>):
        Define this partial specialization to true unconditionally.
        * testsuite/std/ranges/p2325.cc: New test.
        * testsuite/std/ranges/single_view.cc (test06): New test.
        * testsuite/std/ranges/view.cc: Adjust now that view doesn't
        require default_initializable.

2022-05-29  Iain Sandoe  <iain@sandoe.co.uk>

        Backported from master:
        2021-03-15  Iain Sandoe  <iain@sandoe.co.uk>

        * testsuite/17_intro/names.cc: Exclude j from the list
        of test symbols for Darwin.

2022-05-29  Iain Sandoe  <iain@sandoe.co.uk>

        Backported from master:
        2021-11-19  Iain Sandoe  <iain@sandoe.co.uk>

        * testsuite/lib/prune.exp: Prune dsymutil (ld64) warning.

2022-05-16  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-05-16  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/prerequisites.xml: Fix attributes for external
        hyperlink.
        * doc/html/manual/setup.html: Regenerate.

2022-05-16  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-05-16  Jonathan Wakely  <jwakely@redhat.com>

        * doc/html/manual/status.html: Regenerate.
        * doc/xml/manual/status_cxx2020.xml: Fix supported version for
        C++20 bit operations.

2022-05-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-04-20  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93602
        * doc/xml/manual/prerequisites.xml: Document libiconv
        workarounds.
        * doc/html/manual/setup.html: Regenerate.
        * src/Makefile.am (CXXLINK): Add $(LTLIBICONV).
        * src/Makefile.in: Regenerate.

2022-05-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-05-06  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/105502
        * include/bits/random.tcc
        (operator>>(basic_istream<C,T>&, normal_distribution<R>&)):
        Update state when __state_avail is false.
        * testsuite/26_numerics/random/normal_distribution/operators/serialize.cc:
        Check that deserialized object equals serialized one.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-12-09  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_iterator.h (operator==, operator<=>): Define
        overloads for homogeneous specializations of reverse_iterator,
        __normal_iterator and move_iterator.

2022-04-26  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-10-21  Patrick Palka  <ppalka@redhat.com>

        * include/bits/stl_iterator.h (common_iterator::__arrow_proxy):
        Make fully constexpr as per LWG 3595.
        (common_iterator::__postfix_proxy): Likewise.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-01-18  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/104098
        * include/bits/stl_iterator.h (reverse_iterator): Check
        __cpp_lib_concepts instead of __cplusplus.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-14  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/range_access.h (ranges::empty): Check whether
        conversion to bool can throw.
        * testsuite/std/ranges/access/empty.cc: Check for correct
        noexcept-specifier.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/102048
        * include/ext/rope (rope::erase(size_type)): Deprecate broken
        function.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-10-01  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100153
        * include/bits/vector.tcc (vector<bool>::_M_shrink_to_fit()):
        When size() is zero just deallocate and reset.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-01  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/span (span(Range&&)): Reorder constraints.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-09  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/26_numerics/random/random_device/cons/token.cc:
        Retry if random devices produce the same value.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-16  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/21_strings/basic_string/modifiers/append/wchar_t/1.cc:
        Fix reads past the end of strings.
        * testsuite/21_strings/basic_string/operations/compare/wchar_t/1.cc:
        Likewise.
        * testsuite/experimental/string_view/operations/compare/wchar_t/1.cc:
        Likewise.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100117
        * testsuite/17_intro/headers/c++1998/49745.cc: Explicitly list
        all C++ headers instead of including <bits/stdc++.h>

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-12-09  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103630
        * libsupc++/exception_ptr.h (make_exception_ptr): Decay the
        template parameter. Use typeid of the static type.
        * testsuite/18_support/exception_ptr/103630.cc: New test.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-01-17  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103650
        * include/Makefile.am: Rename LT_OBJDIR and STDC_HEADERS.
        * include/Makefile.in: Regenerate.
        * testsuite/17_intro/headers/c++1998/103650.cc: New test.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-02-04  Jonathan Wakely  <jwakely@redhat.com>

        * include/experimental/bits/fs_ops.h (fs::copy_file): Remove
        noexcept.
        (fs::create_directories): Likewise.
        (fs::remove_all): Likewise.
        * src/filesystem/ops.cc (fs::copy_file): Remove noexcept.
        (fs::create_directories): Likewise.
        (fs::remove_all): Likewise.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-04-01  Jonathan Wakely  <jwakely@redhat.com>

        * include/experimental/bits/fs_fwd.h (copy_file): Remove
        incorrect noexcept from declaration.
        * include/experimental/bits/fs_path.h (path::begin, path::end):
        Add noexcept to declarations, to match definitions.

2022-04-26  Timm Bäder  <tbaeder@redhat.com>

        Backported from master:
        2022-04-01  Timm Bäder  <tbaeder@redhat.com>

        * include/bits/fs_ops.h: Fix filename in Doxygen comment.
        * include/experimental/bits/fs_ops.h: Likewise.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-04-20  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/21_strings/basic_string_view/operations/copy/char/constexpr.cc:
        Check correct feature test macro.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-04-14  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/intro.xml: Fix comment.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-03-03  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/17_intro/names.cc (func): Undef on AIX.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-01-27  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/range_access.h (ranges::advance): Avoid signed
        overflow. Do nothing if already equal to desired result.
        * testsuite/24_iterators/range_operations/advance_overflow.cc:
        New test.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-01-06  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/ext/rope/pthread7-rope.cc: Add dg-timeout-factor.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-01-06  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103911
        * include/std/charconv (__from_chars_alpha_to_num): Return
        char instead of unsigned char. Change invalid return value to
        127 instead of using numeric trait.
        (__from_chars_alnum): Fix comment. Do not use std::isdigit.
        Change type of variable to char.

2022-04-26  Pavel I. Kryukov  <pavel.kryukov@phystech.edu>

        Backported from master:
        2022-01-06  Pavel I. Kryukov  <pavel.kryukov@phystech.edu>
                    Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103853
        * include/bits/forward_list.tcc (forward_list::merge): Check for
        self-merge.
        * testsuite/23_containers/forward_list/operations/merge.cc: New test.

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-12-14  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/regex_compiler.tcc (_Compiler::_M_match_token):
        Use reserved name for parameter.
        * testsuite/17_intro/names.cc: Check "token".

2022-04-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-25  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/17_intro/names.cc: Check 'sz'.

2022-04-14  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/status_cxx1998.xml: Refer to GCC 10 not
        mainline.
        * doc/xml/manual/status_cxx2011.xml: Likewise.
        * doc/xml/manual/status_cxx2014.xml: Likewise.
        * doc/xml/manual/status_cxx2017.xml: Likewise.
        * doc/xml/manual/status_cxx2020.xml: Likewise.
        * doc/xml/manual/status_cxxtr1.xml: Likewise.
        * doc/xml/manual/status_cxxtr24733.xml: Likewise.
        * doc/html/manual/status.html: Regenerate.

2022-02-17  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-10-21  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/102358
        * include/bits/stl_iterator.h (__niter_base): Make constexpr
        for C++20.
        (__miter_base): Likewise.
        * testsuite/25_algorithms/move/constexpr.cc: New test.

2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-18  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/char_traits.h (__gnu_cxx::char_traits::move):
        Do not compare unrelated pointers during constant evaluation.
        * testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc:
        Improve tests for char_traits::move.

2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103877
        * doc/xml/faq.xml: Add '-x c++' to preprocessor command.
        * doc/html/faq.html: Regenerate.

2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-12-04  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103549
        * include/bits/regex.h (match_results): Give names to template
        parameters in first declaration.
        (match_results::_M_begin): Add default member-initializer.

2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-30  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103453
        * config/allocator/malloc_allocator_base.h
        (_GLIBCXX_SANITIZE_STD_ALLOCATOR): Define for Clang.
        * config/allocator/new_allocator_base.h
        (_GLIBCXX_SANITIZE_STD_ALLOCATOR): Likewise.

2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        * python/libstdcxx/v6/printers.py (StdErrorCodePrinter): Strip
        versioned namespace from the type name that is printed.

2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-28  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/alloc_traits.h (allocator_traits): Add explicit
        specialization for allocator<void>. Improve doxygen comments.
        * include/bits/allocator.h (allocator<void>): Restore for the
        versioned namespace.
        (allocator<void>::construct, allocator<void>::destroy): Remove.
        * include/ext/extptr_allocator.h (_Extptr_allocator<void>):
        Add default constructor and converting constructor.

2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-23  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103086
        * testsuite/libstdc++-prettyprinters/cxx11.cc: Check unique_ptr
        with non-empty pointer and non-empty deleter.

2022-01-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-04  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103086
        * python/libstdcxx/v6/printers.py (_tuple_impl_get): New helper
        for accessing the tuple element stored in a _Tuple_impl node.
        (tuple_get): New function for accessing a tuple element.
        (unique_ptr_get): New function for accessing a unique_ptr.
        (UniquePointerPrinter, StdPathPrinter): Use unique_ptr_get.
        * python/libstdcxx/v6/xmethods.py (UniquePtrGetWorker): Cast
        tuple to its base class before accessing _M_head_impl.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-07-22  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101571
        * include/bits/ranges_uninitialized.h (_DestroyGuard): Change
        constructor parameter to reference and use addressof.
        * testsuite/util/testsuite_iterators.h: Define deleted operator&
        overloads for test iterators.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-19  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101965
        * include/std/charconv (__to_chars_i): Remove redundant check.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-10-22  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/102894
        * include/std/any (make_any): Add SFINAE constraint.
        * testsuite/20_util/any/102894.cc: New test.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/102270
        * include/std/tuple (_Head_base, _Tuple_impl): Add
        _GLIBCXX20_CONSTEXPR to allocator-extended constructors.
        (tuple<>::swap(tuple&)): Add _GLIBCXX20_CONSTEXPR.
        * testsuite/20_util/tuple/cons/102270.cc: New test.
        * testsuite/util/testsuite_allocator.h (SimpleAllocator): Add
        constexpr to constructor so it can be used for C++20 tests.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-09  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/23_containers/unordered_map/cons/default.cc: Add
        equality comparison operators to allocator.
        * testsuite/23_containers/unordered_set/cons/default.cc:
        Likewise.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-07-20  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100863
        * include/bits/hashtable.h (_Hashtable): Conditionally delete
        default constructor by deriving from _Enable_default_constructor.
        Construct that base-class explicitly in all non-forwarding,
        non-defaulted constructors.
        * testsuite/23_containers/unordered_map/cons/default.cc: New test.
        * testsuite/23_containers/unordered_set/cons/default.cc: New test.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-02  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100863
        PR libstdc++/65816
        * include/bits/hashtable_policy.h (_Hashtable_ebo_helper):
        Value-initialize subobject.
        * testsuite/23_containers/unordered_map/allocator/default_init.cc:
        Remove XFAIL.
        * testsuite/23_containers/unordered_set/allocator/default_init.cc:
        Remove XFAIL.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-09-28  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/move.h (forward(remove_reference_t<T>&&)):
        Improve text of static_assert.
        * testsuite/20_util/forward/c_neg.cc: Adjust dg-error.
        * testsuite/20_util/forward/f_neg.cc: Likewise.

2021-11-26  Antony Polukhin  <antoshkka@gmail.com>

        Backported from master:
        2021-08-17  Antony Polukhin  <antoshkka@gmail.com>
                    Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/random.tcc (seed_seq::seed_seq): Reserve capacity
        if distance is O(1).
        * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
        line number.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-12  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101870
        * include/c_global/cmath (hypot): Use __promoted_t.
        (lerp): Add new overload accepting any arithmetic types.
        * include/ext/type_traits.h (__promoted_t): New alias template.
        * testsuite/26_numerics/lerp.cc: Moved to...
        * testsuite/26_numerics/lerp/1.cc: ...here.
        * testsuite/26_numerics/lerp/constexpr.cc: New test.
        * testsuite/26_numerics/lerp/version.cc: New test.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/27_io/types/1.cc: Add c++11 target selector to
        warnings.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-11  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/headers/memory/synopsis.cc: Define C++98
        alternative for macro.
        * testsuite/20_util/shared_ptr/creation/99006.cc: Add effective
        target keyword.
        * testsuite/25_algorithms/copy/debug/99402.cc: Avoid C++11
        syntax.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/23_containers/array/comparison_operators/96851.cc:
        Skip test in debug mode.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_iterator.h: Include required header for
        std::iterator class template and iterator category tags.

2021-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-25  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101608
        * include/bits/ranges_algobase.h (__fill_n_fn): Check for
        constant evaluation before using memset.
        * testsuite/25_algorithms/fill_n/constrained.cc: Check
        byte-sized values as well.

2021-11-23  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-23  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103381
        * include/ext/bitmap_allocator.h: Include <bits/stl_function.h>
        instead of <functional>.

2021-11-01  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/valarray (begin, end): Remove nodiscard attribute.

2021-11-01  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-11-01  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/103022
        * include/std/valarray (begin, end): Do not dereference an empty
        valarray. Add noexcept and [[nodiscard]].
        * testsuite/26_numerics/valarray/range_access.cc: Check empty
        valarray. Check iterator properties. Run as well as compiling.
        * testsuite/26_numerics/valarray/range_access2.cc: Likewise.
        * testsuite/26_numerics/valarray/103022.cc: New test.

2021-10-13  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-10-13  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/28_regex/match_results/102667.C: Moved to...
        * testsuite/28_regex/match_results/102667.cc: ...here.

2021-10-13  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/21_strings/basic_string_view/requirements/trivially_copyable.cc:
        Use -std=gnu++17 option.

2021-10-13  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-20  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/90787
        * testsuite/27_io/filesystem/iterators/directory_iterator.cc:
        Use new __gnu_test::permissions_are_testable() function.
        * testsuite/27_io/filesystem/iterators/recursive_directory_iterator.cc:
        Likewise.
        * testsuite/27_io/filesystem/operations/exists.cc: Likewise.
        * testsuite/27_io/filesystem/operations/is_empty.cc: Likewise.
        * testsuite/27_io/filesystem/operations/remove.cc: Likewise.
        * testsuite/27_io/filesystem/operations/remove_all.cc: Likewise.
        * testsuite/27_io/filesystem/operations/status.cc: Likewise.
        * testsuite/27_io/filesystem/operations/symlink_status.cc:
        Likewise.
        * testsuite/27_io/filesystem/operations/temp_directory_path.cc:
        Likewise.
        * testsuite/experimental/filesystem/iterators/directory_iterator.cc:
        Likewise.
        * testsuite/experimental/filesystem/iterators/recursive_directory_iterator.cc:
        Likewise.
        * testsuite/experimental/filesystem/operations/exists.cc:
        Likewise.
        * testsuite/experimental/filesystem/operations/is_empty.cc:
        Likewise.
        * testsuite/experimental/filesystem/operations/remove.cc:
        Likewise.
        * testsuite/experimental/filesystem/operations/remove_all.cc:
        Likewise.
        * testsuite/experimental/filesystem/operations/temp_directory_path.cc:
        Likewise.
        * testsuite/util/testsuite_fs.h (__gnu_test::permissions_are_testable):
        New function to guess whether testing permissions will work.

2021-10-13  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/27_io/filesystem/operations/remove_all.cc: Remove
        test directory after making it writable again.
        * testsuite/experimental/filesystem/operations/remove_all.cc:
        Likewise.

2021-10-13  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-22  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/random.h (seed_seq): Constrain initializer-list
        constructor.
        * include/bits/random.tcc (seed_seq): Add template parameter.
        * testsuite/26_numerics/random/seed_seq/cons/default.cc: Check
        for noexcept.
        * testsuite/26_numerics/random/seed_seq/cons/initlist.cc: Check
        constraints.

2021-10-13  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-12  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/25_algorithms/pstl/alg_nonmodifying/find_end.cc:
        Increase dg-timeout-factor to 4. Fix -Wunused-parameter
        warnings. Replace bitwise AND with logical AND in loop
        condition.
        * testsuite/25_algorithms/pstl/alg_nonmodifying/search_n.cc:
        Replace bitwise AND with logical AND in loop condition.
        * testsuite/util/pstl/test_utils.h: Remove unused parameter
        names.

2021-10-13  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-04-28  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/100187
        PR libstdc++/100237
        PR libstdc++/100249
        PR libstdc++/100287
        * include/bits/ranges_algo.h (__search_n_fn::operator()): Give
        the __value_comp lambda an explicit bool return type.
        (__is_permutation_fn::operator()): Give the __proj_scan local
        variable auto&& return type.  Give the __comp_scan lambda an
        explicit bool return type.
        (__remove_fn::operator()): Give the __pred lambda an explicit
        bool return type.
        (__partition_fn::operator()): Don't std::move __first twice
        when returning an empty subrange.
        (__min_fn::operator()): Don't std::move __comp.
        (__max_fn::operator()): Likewise.
        (__minmax_fn::operator()): Likewise.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-08-02  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/101599
        * include/bits/ranges_algo.h (__reverse_copy_fn::operator()):
        Add missing std::move in return statement.
        (__partition_copy_fn::operator()): Rename templtae parameter
        _O2 to _Out2.  Uglify function parameters out_true and out_false.
        * include/bits/ranges_algobase.h (__copy_or_move): Add missing
        std::move to recursive call that unwraps a __normal_iterator
        output iterator.
        * testsuite/25_algorithms/copy/constrained.cc (test06): New test.
        * testsuite/25_algorithms/move/constrained.cc (test05): New test.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-08-02  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/101589
        * include/std/ranges (lazy_split_view::_InnerIter::base): Make
        the const& overload unconstrained and return a const reference
        as per LWG 3533.  Make unconditionally noexcept.
        (elements_view::base): Revert accidental r12-569 change.
        (elements_view::_Iterator::base): Make the const& overload
        unconstrained and return a const reference as per LWG 3533.
        Make unconditionally noexcept.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-08-02  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/101483
        * include/std/ranges (join_view::_Iterator::_Iterator): Add
        missing std::move.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-06-20  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (split_view::_InnerIter::base): Define as
        per P2210.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-06-19  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (transform_view::_Iterator::_S_iter_concept):
        Consider _Base instead of _Vp as per LWG 3555.
        (elements_view::_Iterator::_S_iter_concept): Likewise.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-06-19  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (split_view::_OuterIter::value_type::begin):
        Remove the non-const overload, and remove the copyable constraint
        on the const overload as per LWG 3553.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-06-19  Patrick Palka  <ppalka@redhat.com>

        * include/bits/stl_iterator.h
        (__detail::__common_iter_use_postfix_proxy): Add
        move_constructible constraint as per LWG 3546.
        (common_iterator::__postfix_proxy): Adjust initializer of
        _M_keep as per LWG 3546.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-06-18  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/100387
        * include/bits/ranges_algo.h (__minmax_fn::operator()): Rewrite
        to limit comparison complexity to 3*N/2.
        (__minmax_element_fn::operator()): Likewise.
        (shift_right): Avoid premature std::move of __result.
        * testsuite/25_algorithms/minmax/constrained.cc (test04, test05):
        New tests.
        * testsuite/25_algorithms/minmax_element/constrained.cc (test02):
        Likewise.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-06-18  Patrick Palka  <ppalka@redhat.com>

        * include/std/concepts (convertible_to): Just use declval as per
        LWG 3557.

2021-10-12  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-05-21  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/100606
        * include/std/ranges (drop_while_view::begin): Assert the
        precondition added by LWG 3490.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/tuple/comparison_operators/overloaded.cc:
        Restore test for operator<.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-10-08  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/27_io/basic_filebuf/close/81256.cc: Moved to...
        * testsuite/27_io/basic_filebuf/close/wchar_t/81256.cc: ...here.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-10-05  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/21_strings/basic_string_view/requirements/trivially_copyable.cc:
        New test.
        * testsuite/23_containers/span/trivially_copyable.cc: New test.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-16  Jonathan Wakely  <jwakely@redhat.com>

        * python/Makefile.am [GLIBCXX_BUILD_DEBUG] (install-data-local):
        Install another copy of the GDB hook.
        * python/Makefile.in: Regenerate.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-17  Jonathan Wakely  <jwakely@redhat.com>

        * python/libstdcxx/v6/printers.py (StdErrorCodePrinter): Define.
        (build_libstdcxx_dictionary): Register printer for
        std::error_code and std::error_condition.
        * testsuite/libstdc++-prettyprinters/cxx11.cc: Test it.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-09-23  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/102425
        * src/c++11/system_error.cc
        (system_error_category::default_error_condition): Add 0 to
        switch.
        * testsuite/19_diagnostics/error_category/102425.cc: New test.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-09-16  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/fs_path.h (advance): Remove non-deducible
        template parameter.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-28  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99876
        * src/c++17/fs_ops.cc (fs::absolute): Call non-throwing form,
        to avoid unnecessary current_path() call.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-09-17  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/26_numerics/valarray/dr630-3.C: Moved to...
        * testsuite/26_numerics/valarray/dr630-3.cc: ...here.
        * testsuite/27_io/basic_iostream/cons/16251.C: Moved to...
        * testsuite/27_io/basic_iostream/cons/16251.cc: ...here.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-09-16  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/102280
        * include/std/span (span(Range&&)): Add constraint to deduction
        guide.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-10-01  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/25_algorithms/is_permutation/2.cc: Include <iterator>.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-10-05  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/integer_comparisons/greater.cc: New test.

2021-10-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-10-11  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/102667
        * include/bits/regex.h (match_result::empty()): Optimize by
        calling the base function directly.
        (match_results::end()): Check _Base_type::empty() not empty().
        * testsuite/28_regex/match_results/102667.C: New test.

2021-08-23  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-23  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (basic_istream_view): Add default template
        argument.
        * testsuite/std/ranges/istream_view.cc: Check it.

2021-08-19  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-19  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100139
        * doc/xml/manual/status_cxx2020.xml: Add P1739R4 to status table.
        * doc/html/manual/status.html: Regenerate.

2021-08-17  Thomas Schwinge  <thomas@codesourcery.com>

        Backported from master:
        2021-08-17  Thomas Schwinge  <thomas@codesourcery.com>

        * testsuite/lib/libstdc++.exp: Avoid illegal argument to verbose,
        continued.

2021-08-11  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-08-11  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101866
        * testsuite/experimental/random/randint.cc: Loop and retry if
        reseed() produces the same sequence.

2021-08-11  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-07-20  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101510
        * src/c++17/fs_ops.cc (fs::create_directories): Use status
        instead of symlink_status.
        * src/filesystem/ops.cc (fs::create_directories): Likewise.
        * testsuite/27_io/filesystem/operations/create_directories.cc:
        Check symlink to existing directory.
        * testsuite/27_io/filesystem/operations/create_directory.cc: Do
        not test with symlinks on Windows.
        * testsuite/experimental/filesystem/operations/create_directories.cc:
        Check symlink to existing directory.
        * testsuite/experimental/filesystem/operations/create_directory.cc:
        Do not test with symlinks on Windows.

2021-08-11  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-07-20  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101510
        * src/c++17/fs_ops.cc (create_dir): Adjust whitespace.
        * testsuite/27_io/filesystem/operations/create_directory.cc:
        Test creating directory with name of existing symlink to
        directory.
        * testsuite/experimental/filesystem/operations/create_directory.cc:
        Likewise.

2021-08-11  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-14  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101056
        * libsupc++/compare (compare_partial_order_fallback): Add
        constraint using reversed parameter order, as per LWG 3465.
        * testsuite/18_support/comparisons/algorithms/fallback.cc:
        Adjust expected result.

2021-08-11  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-14  Jonathan Wakely  <jwakely@redhat.com>

        * libsupc++/compare (__decayed_same_as): New helper concept.
        (strong_order, weak_order, partial_order): Constrain with new
        concept instead of using static_assert.
        (compare_strong_order_fallback, compare_weak_order_fallback)
        (compare_partial_order_fallback): Likewise. Do not deduce return
        types. Remove redundant if-constexpr checks.
        * testsuite/18_support/comparisons/algorithms/fallback.cc: New test.

2021-08-10  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-14  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100894
        * include/std/type_traits (__common_ref_impl<X&, Y&>): Only
        use the type if it's a reference.
        * testsuite/20_util/common_reference/100894.cc: New test.

2021-07-22  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-15  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96657
        * libsupc++/Makefile.am: Add atomicity.cc here.
        * src/c++98/Makefile.am: Remove it from here.
        * libsupc++/Makefile.in: Regenerate.
        * src/c++98/Makefile.in: Regenerate.
        * testsuite/18_support/exception_ptr/96657.cc: New test.

2021-07-22  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-07  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/98842
        * include/std/optional (operator<=>(const optional<T>& const U&)):
        Add missing constraint and add workaround for template
        recursion.
        * testsuite/20_util/optional/relops/three_way.cc: Check that
        type without equality comparison cannot be compared when wrapped
        in std::optional.

2021-07-14  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-07-13  Jonathan Wakely  <jwakely@redhat.com>

        PR c++/101361
        * include/std/string_view (ends_with): Use traits_type::compare
        directly.

2021-07-14  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-07-12  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101411
        * include/std/span (as_writable_bytes): Add requires-clause.
        * testsuite/23_containers/span/101411.cc: New test.

2021-07-06  Avi Kivity  <avi@scylladb.com>

        Backported from master:
        2021-06-07  Avi Kivity  <avi@scylladb.com>

        PR libstdc++/100900
        * include/std/ranges (elements_view::__iter_cat::_S_iter_cat):
        Add missing typename.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/95833
        * include/std/numeric (reduce(Iter, Iter, T, BinaryOp)): Replace
        incorrect static_assert with ones matching the 'Mandates'
        conditions in the standard.
        * testsuite/26_numerics/reduce/95833.cc: New test.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/variant (__same_types, __check_visitor_results):
        Remove.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-04  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/future (promise::set_value): Check for existence
        of shared state before dereferncing it.
        (promise::set_exception, promise::set_value_at_thread_exit)
        (promise::set_exception_at_thread_exit): Likewise.
        (promise<R&>::set_value, promise<R&>::set_exception)
        (promise<R&>::set_value_at_thread_exit)
        (promise<R&>::set_exception_at_thread_exit): Likewise.
        (promise<void>::set_value, promise<void>::set_exception)
        (promise<void>::set_value_at_thread_exit)
        (promise<void>::set_exception_at_thread_exit): Likewise.
        * testsuite/30_threads/promise/members/at_thread_exit2.cc:
        Remove unused variable.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-04  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/basic_string.h (basic_string(const CharT*, const A&)):
        Do not do arithmetic on null pointer.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-04  Jonathan Wakely  <jwakely@redhat.com>

        * include/ext/pb_ds/detail/cc_hash_table_map_/cc_ht_map_.hpp
        (find_key_pointer(key_const_reference, false_type))
        (find_key_pointer(key_const_reference, true_type)): Do not
        dereference null pointer.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-04  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/from_chars/3.cc: Use unsigned type to avoid
        overflow.
        * testsuite/24_iterators/reverse_iterator/2.cc: Do not add
        non-zero value to null pointer.
        * testsuite/25_algorithms/copy_backward/move_iterators/69478.cc:
        Use past-the-end iterator for result.
        * testsuite/25_algorithms/move_backward/69478.cc: Likewise.
        * testsuite/25_algorithms/move_backward/93872.cc: Likewise.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-04  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100384
        * include/std/variant (__get_t): New alias template yielding the
        return type of std::get<N> on a variant.
        (__visit_result_t): New alias template yielding the result of
        std::visit.
        (__same_types): Move into namespace __detail::__variant.
        (__check_visitor_results): Likewise. Use __invoke_result_t and
        __get_t.
        (__check_visitor_result): Remove.
        (visit): Use __visit_result_t for return type.
        * testsuite/20_util/variant/100384.cc: New test.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-22  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99006
        * include/bits/shared_ptr.h (allocate_shared): Assert that _Tp
        is not an array type.
        * include/bits/shared_ptr_base.h (__allocate_shared): Likewise.
        * testsuite/20_util/shared_ptr/creation/99006.cc: New test.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-11  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/allocator.h (allocator<void>) [C++20]: Add
        missing noexcept to constructor. Restore missing POCMA and
        is_always_equal_traits.
        * include/bits/memoryfwd.h (allocator_traits): Declare.
        * include/ext/malloc_allocator.h (malloc_allocator::allocate):
        Add nodiscard attribute. Add static assertion for LWG 3307.
        * include/ext/new_allocator.h (new_allocator::allocate): Add
        static assertion for LWG 3307.
        * testsuite/20_util/allocator/void.cc: Check that converting
        constructor is noexcept. Check for propagation traits and
        size_type and difference_type. Check that pointer and
        const_pointer are gone in C++20.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-10  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/shared_ptr_base.h (__shared_count(unique_ptr&&)):
        Initialize a non-reference deleter from an rvalue, as per LWG
        3548.
        (__shared_ptr::_UniqCompatible): Add missing constraint.
        * testsuite/20_util/shared_ptr/cons/lwg3548.cc: New test.
        * testsuite/20_util/shared_ptr/cons/unique_ptr_deleter.cc: Check
        constraints.

2021-06-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-17  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/91488
        * include/bits/basic_string.h (__cpp_lib_constexpr_string): Only
        define C++20 value when std::is_constant_evaluated is available.
        * include/bits/char_traits.h (__cpp_lib_constexpr_char_traits):
        Likewise.
        (__constant_string_p, __constant_array_p): Give external
        linkage.
        * include/std/version (__cpp_lib_constexpr_char_traits)
        (__cpp_lib_constexpr_string): Only define C++20 values when
        is_constant_evaluated is available.

2021-06-14  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-10  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/scoped_allocator/69293_neg.cc: Add dg-error
        for additional errors in C++20.
        * testsuite/20_util/uses_allocator/69293_neg.cc: Likewise.
        * testsuite/20_util/uses_allocator/cons_neg.cc: Likewise.

2021-06-14  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-09  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100982
        * include/std/optional (optional::operator=(const optional<U>&)):
        Fix value category used in is_assignable check.
        * testsuite/20_util/optional/assignment/100982.cc: New test.

2021-06-14  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-14  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/101034
        * include/std/any (any(in_place_t<T>, initializer_list<U>, A&&...))
        (any::emplace<T>(initializer_list<U>, A&&...)): Fix constraint
        to use lvalue.
        * testsuite/20_util/any/cons/101034.cc: New test.

2021-06-10  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-06-03  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/100770
        * include/bits/ranges_algo.h (__detail::__can_reread_output):
        Factor out this concept from ...
        (__unique_copy_fn::operator()): ... here.  Use the concept
        throughout.
        * testsuite/std/ranges/range.cc: Remove now ill-formed use
        of range_value_t on an output_range.
        * testsuite/util/testsuite_iterators.h (output_iterator_wrapper):
        Define value_type, pointer and reference member types to void.

2021-06-10  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-05-21  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/100690
        * include/std/ranges (iota_view::_Sentinel::_M_distance_from):
        Split out this member function from ...
        (iota_view::_Sentinel::operator-): ... here, for sake of access
        control.
        * testsuite/std/ranges/iota/iota_view.cc (test05): New test.

2021-06-10  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-05-06  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (filter_view::_Iterator::base): Make the
        const& overload unconstrained and return a const reference as
        per LWG 3533.  Make unconditionally noexcept.
        (transform_view::_Iterator::base): Likewise.
        (elements_view::_Iterator::base): Likewise.

2021-06-10  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-05-06  Patrick Palka  <ppalka@redhat.com>

        * include/bits/stl_iterator.h (move_iterator::base): Make the
        const& overload unconstrained and return a const reference as
        per LWG 3391.  Make unconditionally noexcept.
        (counted_iterator::base): Likewise.
        * testsuite/24_iterators/move_iterator/lwg3391.cc: New test.
        * testsuite/24_iterators/move_iterator/move_only.cc: Adjust
        has_member_base concept to decay-copy the result of base().

2021-06-10  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-05-18  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/100631
        * include/std/ranges (elements_view::_Sentinel::operator-): Use
        _M_distance_from in the other operator- overload too.
        * testsuite/std/ranges/adaptors/elements.cc (test06): Augment test.

2021-06-10  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-05-18  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/100631
        * include/std/ranges (elements_view::_Iterator): Also befriend
        _Sentinel<!_Const>.
        (elements_view::_Sentinel::_M_equal): Templatize.
        (elements_view::_Sentinel::_M_distance_from): Split out from ...
        (elements_view::_Sentinel::operator-): ... here.  Depend on
        _Base2 instead of _Base in the return type.
        * testsuite/std/ranges/adaptors/elements.cc (test06, test07):
        New tests.

2021-06-10  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-05-20  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/100639
        * include/bits/stl_iterator.h (reverse_iterator::difference_type):
        In C++20 mode, define in terms of iter_difference_t as per P0896R4.
        (reverse_iterator::reference): Likewise, but with iter_reference_t.
        (reverse_iterator::value_type): Likewise, but with iter_value_t.
        * testsuite/std/ranges/adaptors/reverse.cc (test08): New test.
        * testsuite/24_iterators/reverse_iterator/100639.cc: New test.

2021-06-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-01  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100833
        * include/bits/range_access.h (ranges::advance(iter, n, sentinel)):
        Fix return value for no-op case.
        * testsuite/24_iterators/range_operations/advance.cc: Test
        return values of three-argument overload.

2021-06-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-05-26  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100768
        * include/bits/range_access.h (ranges::advance)
        (ranges::distance, ranges::next, ranges::prev): Replace
        function templates with function objects.
        * testsuite/24_iterators/headers/iterator/synopsis_c++20.cc:
        Adjust for changes to function objects.
        * testsuite/std/ranges/adaptors/elements.cc: Add using
        declarations for names from namespace ranges.
        * testsuite/std/ranges/adaptors/transform.cc: Likewise.
        * testsuite/24_iterators/range_operations/100768.cc: New test.

2021-06-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-06-01  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99453
        * python/Makefile.am: Use archive name for printer hook if no
        dynamic library name is available.
        * python/Makefile.in: Regenerate.

2021-06-03  Philippe Blain  <levraiphilippeblain@gmail.com>

        Backported from master:
        2021-04-21  Philippe Blain  <levraiphilippeblain@gmail.com>
                    Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99453
        * python/Makefile.am: Install libstdc++*-gdb.py more robustly.
        * python/Makefile.in: Regenerate.

2021-05-17  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100630
        * include/bits/fs_path.h (__is_constructible_from): Test
        construction from a const lvalue, not an rvalue.
        * include/experimental/bits/fs_path.h (__is_constructible_from):
        Likewise.
        * testsuite/27_io/filesystem/path/construct/100630.cc: New test.
        * testsuite/experimental/filesystem/path/construct/100630.cc:
        New test.

2021-05-17  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-03-11  Jonathan Wakely  <jwakely@redhat.com>

        * python/libstdcxx/v6/printers.py (find_type): Use tag attribute
        instead of unqualified() method.

2021-05-05  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-05-05  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (transform_view::_Iterator::iter_swap):
        Remove as per LWG 3520.
        (join_view::_Iterator::iter_swap): Add indirectly_swappable
        constraint as per LWG 3517.

2021-05-04  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-04-30  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (split_view::_InnerIter::operator++):
        Depend on _Base instead of _Vp directly, as per LWG 3532.

2021-05-04  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-04-20  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/95983
        * include/bits/stl_iterator.h (__detail::__move_iter_cat):
        Define.
        (move_iterator): Derive from the above in C++20 in order to
        conditionally define iterator_category as per P2259.
        (move_iterator::__base_cat): No longer used, so remove.
        (move_iterator::iterator_category): Remove in C++20.
        (__detail::__common_iter_use_postfix_proxy): Define.
        (common_iterator::_Proxy): Rename to ...
        (common_iterator:__arrow_proxy): ... this.
        (common_iterator::__postfix_proxy): Define as per P2259.
        (common_iterator::operator->): Adjust.
        (common_iterator::operator++): Adjust as per P2259.
        (iterator_traits<common_iterator>::_S_iter_cat): Define.
        (iterator_traits<common_iterator>::iterator_category): Change as
        per P2259.
        (__detail::__counted_iter_value_type): Define.
        (__detail::__counted_iter_concept): Define.
        (__detail::__counted_iter_cat): Define.
        (counted_iterator): Derive from the above three classes in order
        to conditionally define value_type, iterator_concept and
        iterator category respectively as per P2259.
        (counted_iterator::operator->): Define as per P2259.
        (incrementable_traits<counted_iterator>): Remove as per P2259.
        (iterator_traits<counted_iterator>): Adjust as per P2259.
        * include/std/ranges (__detail::__iota_view_iter_cat): Define.
        (iota_view::_Iterator): Derive from the above in order to
        conditionally define iterator_category as per P2259.
        (iota_view::_S_iter_cat): Rename to ...
        (iota_view::_S_iter_concept): ... this.
        (iota_view::iterator_concept): Use it to apply LWG 3291 changes.
        (iota_view::iterator_category): Remove.
        (__detail::__filter_view_iter_cat): Define.
        (filter_view::_Iterator): Derive from the above in order to
        conditionally define iterator_category as per P2259.
        (filter_view::_Iterator): Move to struct __filter_view_iter_cat.
        (filter_view::_Iterator::iterator_category): Remove.
        (transform_view::_Base): Define.
        (transform_view::__iter_cat): Define.
        (transform_view::_Iterator): Derive from the above in order to
        conditionally define iterator_category as per P2259.
        (transform_view::_Iterator::_Base): Just alias
        transform_view::_Base.
        (transform_view::_Iterator::_S_iter_cat): Move to struct
        transform_view::__iter_cat.
        (transform_view::_Iterator::iterator_category): Remove.
        (transform_view::_Sentinel::_Base): Just alias
        transform_view::_Base.
        (join_view::_Base): Define.
        (join_view::_Outer_iter): Define.
        (join_view::_Inner_iter): Define.
        (join_view::_S_ref_is_glvalue): Define.
        (join_view::__iter_cat): Define.
        (join_view::_Iterator): Derive from it in order to conditionally
        define iterator_category as per P2259.
        (join_view::_Iterator::_Base): Just alias join_view::_Base.
        (join_view::_Iterator::_S_ref_is_glvalue): Just alias
        join_view::_S_ref_is_glvalue.
        (join_view::_Iterator::_S_iter_cat): Move to struct
        transform_view::__iter_cat.
        (join_view::_Iterator::_Outer_iter): Just alias
        join_view::_Outer_iter.
        (join_view::_Iterator::_Inner_iter): Just alias
        join_view::_Inner_iter.
        (join_view::_Iterator::iterator_category): Remove.
        (join_view::_Sentinel::_Base): Just alias join_view::_Base.
        (__detail::__split_view_outer_iter_cat): Define.
        (__detail::__split_view_inner_iter_cat): Define.
        (split_view::_Base): Define.
        (split_view::_Outer_iter): Derive from __split_view_outer_iter_cat
        in order to conditionally define iterator_category as per P2259.
        (split_view::_Outer_iter::iterator_category): Remove.
        (split_view::_Inner_iter): Derive from __split_view_inner_iter_cat
        in order to conditionally define iterator_category as per P2259.
        (split_view::_Inner_iter::_S_iter_cat): Move to
        __split_view_inner_iter_cat.
        (split_view::_Inner_iter::iterator_category): Remove.
        (elements_view::_Base): Define.
        (elements_view::__iter_cat): Define.
        (elements_view::_Iterator): Derive from the above in order to
        conditionall define iterator_category as per P2259.
        (elements_view::_Iterator::_Base): Just alias
        elements_view::_Base.
        (elements_view::_Iterator::_S_iter_concept)
        (elements_view::_Iterator::iterator_concept): Define as per
        P2259.
        (elements_view::_Iterator::iterator_category): Remove.
        (elements_view::_Sentinel::_Base): Just alias
        elements_view::_Base.
        * testsuite/24_iterators/headers/iterator/synopsis_c++20.cc:
        Adjust constraints on iterator_traits<counted_iterator>.
        * testsuite/std/ranges/p2259.cc: New test.

2021-05-03  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-04-27  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/100290
        * include/std/ranges (join_view::_Iterator::operator++): Correct
        the return type of the lambda to avoid returning a copy of
        _M_parent->_M_inner.
        * testsuite/std/ranges/adaptors/join.cc (test10): New test.

2021-04-30  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-30  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/basic_string.h (__cpp_lib_constexpr_string):
        Only define for C++17 and later.

2021-04-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-26  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100259
        * include/experimental/internet (net::ip::make_error_code)
        (net::ip::make_error_condition, net::ip::make_network_v4)
        (net::ip::operator==(const udp&, const udp&)): Add 'inline'.

2021-04-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-28  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/basic_string.h (__cpp_lib_constexpr_string): Define.
        * include/std/version (__cpp_lib_constexpr_string): Define.
        * testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc:
        Check for __cpp_lib_constexpr_string.
        * testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc:
        Likewise.
        * testsuite/21_strings/char_traits/requirements/version.cc: New test.

2021-04-21  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100180
        * testsuite/experimental/net/internet/address/v6/members.cc:
        Require gthreads.

2021-04-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-04-08  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (__detail::find): Define.
        (split_view::_OuterIter::operator++): Apply proposed resolution
        of LWG 3505.
        * testsuite/std/ranges/adaptors/split.cc (test10): New test.

2021-04-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-04-08  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (__detail::find_if): Simplify.
        (__detail::find_if_not): Likewise.
        (__detail::min): Remove.
        (__detail::mismatch): Simplify.
        (take_view::size): Use std::min instead of __detail::min.

2021-04-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2021-04-08  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (__detail::__returnable_element): New
        concept.
        (elements_view): Use this concept in its constraints.  Add
        missing private access specifier.
        (elements_view::_S_get_element): Define as per LWG 3502.
        (elements_view::operator*, elements_view::operator[]): Use
        _S_get_element.
        (elements_view::operator++): Remove unnecessary constraint
        as per LWG 3492.
        * testsuite/std/ranges/adaptors/elements.cc (test05): New test.

2021-04-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-10-31  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/97600
        * include/std/ranges (basic_istream_view::begin): Initialize
        _Iterator from 'this' instead of '*this'.
        (basic_istream_view::_Iterator::_Iterator): Adjust constructor
        accordingly.
        (filter_view::_Iterator::_Iterator): Take a filter_view*
        argument instead of a filter_view& argument.
        (filter_view::_Sentinel::_Sentinel): Likewise.
        (filter_view::begin): Initialize _Iterator from 'this' instead
        of '*this'.
        (filter_view::end): Likewise.
        (transform_view::_Iterator::_Iterator): Take a _Parent* instead
        of a _Parent&.
        (filter_view::_Iterator::operator+): Adjust accordingly.
        (filter_view::_Iterator::operator-): Likewise.
        (filter_view::begin): Initialize _Iterator from 'this' instead
        of '*this'.
        (filter_view::end): Likewise.
        (join_view::_Iterator): Take a _Parent* instead of a _Parent&.
        (join_view::_Sentinel): Likewise.
        (join_view::begin): Initialize _Iterator from 'this' instead of
        '*this'.
        (join_view::end): Initialize _Sentinel from 'this' instead of
        '*this'.
        (split_view::_OuterIter): Take a _Parent& instead of a _Parent*.
        (split_view::begin): Initialize _OuterIter from 'this' instead
        of '*this'.
        (split_view::end): Likewise.
        * testsuite/std/ranges/97600.cc: New test.

2021-04-19  François Dumont  <fdumont@gcc.gnu.org>

        PR libstdc++/99402
        * include/debug/helper_functions.h (__can_advance(_InputIterator,
        const std::pair<_Diff, _Distance_precision>&, int)): New.
        (__can_advance(const _Safe_iterator<>&,
        const std::pair<_Diff, _Distance_precision>&, int)): New.
        * include/debug/macros.h (__glibcxx_check_can_increment_dist): New,
        use latter.
        (__glibcxx_check_can_increment_range): Adapt to use latter.
        (__glibcxx_check_can_decrement_range): Likewise.
        * include/debug/safe_iterator.h
        (_Safe_iterator<>::_M_can_advance(const std::pair<_Diff, _Distance_precision>&,
        int)): New.
        (__can_advance(const _Safe_iterator<>&,
        const std::pair<_Diff, _Distance_precision>&, int)): New.
        * include/debug/safe_iterator.tcc
        (_Safe_iterator<>::_M_can_advance(const std::pair<_Diff, _Distance_precision>&,
        int)): New.
        (_Safe_iterator<>::_M_valid_range(const _Safe_iterator<>&,
        std::pair<difference_type, _Distance_precision>&, bool)): Adapt for
        __dp_sign_max_size.
        (__copy_move_a): Adapt to use __glibcxx_check_can_increment_dist.
        (__copy_move_backward_a): Likewise.
        (__equal_aux): Likewise.
        * include/debug/stl_iterator.h (__can_advance(const std::reverse_iterator<>&,
        const std::pair<_Diff, _Distance_precision>&, int)): New.
        (__can_advance(const std::move_iterator<>&,
        const std::pair<_Diff, _Distance_precision>&, int)): New.
        * testsuite/25_algorithms/copy/debug/99402.cc: New test.

2021-04-19  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-26  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97570
        * libsupc++/new_opa.cc: Declare size_t in global namespace.
        Remove unused header.

2021-04-13  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-13  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100060
        * include/std/bit: Only include <ext/numeric_traits.h> for
        hosted build, use <limits> otherwise.

2021-04-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-12  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/100044
        * include/std/ranges (__detail::__iterator_sentinel_pair):
        Remove helper concept.
        (subrange(_Pr), subrange(Pr, __make_unsigned_like<...>)): Remove
        deduction guides, as per LWG 3404.
        * testsuite/std/ranges/subrange/lwg3282_neg.cc: Check that class
        template argument deduction fails.

2021-04-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-24  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/iterator_concepts.h (indirectly_readable): Add
        partial specializations to resolve ambiguities (LWG 3446).
        * testsuite/24_iterators/associated_types/readable.traits.cc:
        Check types with both value_type and element_type.

2021-04-09  Jonathan Wakely  <jwakely@redhat.com>

        PR bootstrap/99983
        * include/bits/hashtable.h (_Hashtable): Fix noexcept-speciofier
        on definition to match the one on the declaration.

2021-04-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-09  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99985
        * include/bits/hashtable.h (_Hashtable::_S_nothrow_move()): Fix
        to be a valid constexpr function in C++11.
        * testsuite/23_containers/unordered_set/cons/99985.cc: New test.

2021-04-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-09  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/fs_fwd.h: Fix doxygen group command.
        * include/bits/streambuf_iterator.h: Likewise.
        * include/std/chrono: Likewise.
        * include/std/memory: Likewise.
        * include/std/thread: Likewise.
        * include/tr1/complex: Likewise.

2021-04-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-08  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/basic_string.h: Tweak doxygen comment.

2021-04-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-08  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/random.h: Fix doxygen group commands.
        * include/bits/regex_constants.h: Likewise.
        * include/tr1/random.h: Likewise.

2021-04-08  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-07-30  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/23_containers/unordered_multiset/cons/noexcept_default_construct.cc:
        Use allocator with the correct value type.
        * testsuite/23_containers/unordered_set/cons/noexcept_default_construct.cc:
        Likewise.

2021-04-08  François Dumont  <fdumont@gcc.gnu.org>

        Backported from master:
        2020-07-29  François Dumont  <fdumont@gcc.gnu.org>

        PR libstdc++/96029
        * include/bits/hashtable.h
        (_Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a, true_type)):
        Add noexcept qualification.
        (_Hashtable(_Hashtable&&)): Fix noexcept qualification.
        (_Hashtable(_Hashtable&&, const allocator_type&)): Add noexcept
        qualification.
        * include/bits/unordered_map.h
        (unordered_map(unordered_map&&, const allocator_type&)): Add noexcept
        qualification.
        (unordered_multimap(unordered_multimap&&, const allocator_type&)):
        Likewise.
        * include/bits/unordered_set.h
        (unordered_set(unordered_set&&, const allocator_type&)): Likewise.
        (unordered_multiset(unordered_multiset&&, const allocator_type&)):
        Likewise.
        * include/debug/unordered_map
        (unordered_map(unordered_map&&, const allocator_type&)): Likewise.
        (unordered_multimap(unordered_multimap&&, const allocator_type&)):
        Likewise.
        * include/debug/unordered_set
        (unordered_set(unordered_set&&, const allocator_type&)): Likewise.
        (unordered_multiset(unordered_multiset&&, const allocator_type&)):
        Likewise.
        * testsuite/23_containers/unordered_map/allocator/default_init.cc:
        New test.
        * testsuite/23_containers/unordered_map/cons/noexcept_default_construct.cc:
        New test.
        * testsuite/23_containers/unordered_map/cons/noexcept_move_construct.cc:
        New test.
        * testsuite/23_containers/unordered_map/modifiers/move_assign.cc:
        New test.
        * testsuite/23_containers/unordered_multimap/cons/noexcept_default_construct.cc:
        New test.
        * testsuite/23_containers/unordered_multimap/cons/noexcept_move_construct.cc:
        New test.
        * testsuite/23_containers/unordered_multiset/cons/noexcept_default_construct.cc:
        New test.
        * testsuite/23_containers/unordered_multiset/cons/noexcept_move_construct.cc:
        New test.
        * testsuite/23_containers/unordered_set/allocator/default_init.cc:
        New test.
        * testsuite/23_containers/unordered_set/cons/noexcept_default_construct.cc:
        New test.
        * testsuite/23_containers/unordered_set/cons/noexcept_move_construct.cc:
        New test.

2021-04-08  François Dumont  <fdumont@gcc.gnu.org>

        Backported from master:
        2020-07-08  François Dumont  <fdumont@gcc.gnu.org>

        PR libstdc++/96029
        * include/bits/stl_tree.h (_Rb_tree_impl(_Rb_tree_impl&&)): Add noexcept
        qualification based only on _Compare one.
        * testsuite/23_containers/map/cons/noexcept_move_construct.cc: Add
        static asserts.
        * testsuite/23_containers/multimap/cons/noexcept_move_construct.cc:
        Likewise.
        * testsuite/23_containers/multiset/cons/noexcept_move_construct.cc:
        Likewise.
        * testsuite/23_containers/set/cons/noexcept_move_construct.cc: Likewise.

2021-04-08  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-07  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99805
        * src/c++17/fs_path.cc (path::_M_split_cmpts): Do not call
        non-const member on _M_pathname, to avoid copy-on-write.
        * testsuite/27_io/filesystem/path/decompose/parent_path.cc:
        Check construction from strings that might be shared.

2021-04-08  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/status_cxx2017.xml: Replace Intel parallelstl
        link with LLVM repo for PSTL.
        * doc/html/manual/status.html: Regenerate.

2021-04-08  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-06  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/alloc_traits.h: Use markdown for code font.
        * include/bits/basic_string.h: Fix @param names.
        * include/bits/regex.h: Fix duplicate @retval names, and rename.
        * include/ext/pb_ds/detail/priority_queue_base_dispatch.hpp: Add
        group open to match existing group close.
        * include/ext/pb_ds/priority_queue.hpp: Add blank line before group
        open.

2021-04-08  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-06  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/atomic_base.h: Fix doxygen group close.
        * include/bits/basic_ios.h: Likewise.
        * include/bits/forward_list.h: Likewise.
        * include/bits/fs_dir.h: Likewise.
        * include/bits/fs_ops.h: Likewise.
        * include/bits/fs_path.h: Likewise.
        * include/bits/functional_hash.h: Likewise.
        * include/bits/gslice.h: Likewise.
        * include/bits/gslice_array.h: Likewise.
        * include/bits/hashtable_policy.h: Likewise.
        * include/bits/indirect_array.h: Likewise.
        * include/bits/locale_classes.h: Likewise.
        * include/bits/locale_facets.h: Likewise.
        * include/bits/locale_facets_nonio.h: Likewise.
        * include/bits/mask_array.h: Likewise.
        * include/bits/refwrap.h: Likewise.
        * include/bits/regex.h: Likewise.
        * include/bits/regex_automaton.h: Likewise.
        * include/bits/regex_compiler.h: Likewise.
        * include/bits/regex_constants.h: Likewise.
        * include/bits/regex_error.h: Likewise.
        * include/bits/regex_executor.h: Likewise.
        * include/bits/regex_scanner.h: Likewise.
        * include/bits/shared_ptr.h: Likewise.
        * include/bits/shared_ptr_atomic.h: Likewise.
        * include/bits/shared_ptr_base.h: Likewise.
        * include/bits/slice_array.h: Likewise.
        * include/bits/specfun.h: Likewise.
        * include/bits/std_function.h: Likewise.
        * include/bits/std_mutex.h: Likewise.
        * include/bits/stl_deque.h: Likewise.
        * include/bits/stl_iterator.h: Likewise.
        * include/bits/stl_iterator_base_types.h: Likewise.
        * include/bits/stl_map.h: Likewise.
        * include/bits/stl_multimap.h: Likewise.
        * include/bits/stl_multiset.h: Likewise.
        * include/bits/stl_numeric.h: Likewise.
        * include/bits/stl_pair.h: Likewise.
        * include/bits/stl_set.h: Likewise.
        * include/bits/stl_uninitialized.h: Likewise.
        * include/bits/stream_iterator.h: Likewise.
        * include/bits/streambuf_iterator.h: Likewise.
        * include/bits/unique_ptr.h: Likewise.
        * include/bits/unordered_map.h: Likewise.
        * include/bits/unordered_set.h: Likewise.
        * include/decimal/decimal: Likewise.
        * include/experimental/any: Likewise.
        * include/experimental/array: Likewise.
        * include/experimental/bits/fs_dir.h: Likewise.
        * include/experimental/bits/fs_fwd.h: Likewise.
        * include/experimental/bits/fs_ops.h: Likewise.
        * include/experimental/bits/fs_path.h: Likewise.
        * include/experimental/buffer: Likewise.
        * include/experimental/internet: Likewise.
        * include/experimental/optional: Likewise.
        * include/experimental/propagate_const: Likewise.
        * include/experimental/socket: Likewise.
        * include/ext/pb_ds/assoc_container.hpp: Likewise.
        * include/ext/pb_ds/detail/priority_queue_base_dispatch.hpp:
        Likewise.
        * include/ext/pb_ds/detail/tree_policy/node_metadata_selector.hpp: Likewise.
        * include/ext/pb_ds/detail/trie_policy/node_metadata_selector.hpp: Likewise.
        * include/ext/pb_ds/detail/types_traits.hpp: Likewise.
        * include/ext/pb_ds/exception.hpp: Likewise.
        * include/ext/pb_ds/priority_queue.hpp: Likewise.
        * include/ext/pb_ds/tag_and_trait.hpp: Likewise.
        * include/ext/random: Likewise.
        * include/std/any: Likewise.
        * include/std/atomic: Likewise.
        * include/std/bitset: Likewise.
        * include/std/chrono: Likewise.
        * include/std/complex: Likewise.
        * include/std/condition_variable: Likewise.
        * include/std/fstream: Likewise.
        * include/std/future: Likewise.
        * include/std/istream: Likewise.
        * include/std/iostream: Likewise.
        * include/std/mutex: Likewise.
        * include/std/numeric: Likewise.
        * include/std/ostream: Likewise.
        * include/std/ratio: Likewise.
        * include/std/shared_mutex: Likewise.
        * include/std/stdexcept: Likewise.
        * include/std/streambuf: Likewise.
        * include/std/system_error: Likewise.
        * include/std/valarray: Likewise.
        * include/std/variant: Likewise.
        * include/tr1/cmath: Likewise.
        * include/tr1/regex: Likewise.
        * include/tr2/dynamic_bitset: Likewise.
        * libsupc++/atomic_lockfree_defines.h: Likewise.
        * libsupc++/exception: Likewise.
        * libsupc++/exception.h: Likewise.
        * libsupc++/exception_ptr.h: Likewise.
        * libsupc++/nested_exception.h: Likewise.

2021-04-08  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-04-08  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/string_view: Adjust Doxygen @file comment.

2021-04-08  Release Manager

        * GCC 10.3.0 released.

2021-04-01  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-14  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99096
        * testsuite/util/testsuite_fs.h: Always include <unistd.h>.

2021-04-01  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-12-17  Jonathan Wakely  <jwakely@redhat.com>

        * config.h.in: Regenerate.
        * config/os/djgpp/error_constants.h: Test POSIX errno macros
        directly, instead of corresponding _GLIBCXX_HAVE_EXXX macros.
        * config/os/mingw32-w64/error_constants.h: Likewise.
        * config/os/mingw32/error_constants.h: Likewise.
        * configure: Regenerate.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-30  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/specialized_algorithms/pstl/*: Add
        dg-timeout-factor.
        * testsuite/25_algorithms/pstl/*: Likewise.
        * testsuite/26_numerics/pstl/*: Likewise.
        * testsuite/28_regex/*: Likewise.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-26  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/28_regex/algorithms/regex_match/basic/string_range_01_03.cc:
        Add dg-timeout-factor directive.
        * testsuite/28_regex/algorithms/regex_match/cstring_bracket_01.cc:
        Likewise.
        * testsuite/28_regex/algorithms/regex_match/ecma/char/backref.cc:
        Likewise.
        * testsuite/28_regex/algorithms/regex_match/ecma/wchar_t/63199.cc:
        Likewise.
        * testsuite/28_regex/algorithms/regex_match/ecma/wchar_t/anymatcher.cc:
        Likewise.
        * testsuite/28_regex/algorithms/regex_match/ecma/wchar_t/cjk_match.cc:
        Likewise.
        * testsuite/28_regex/algorithms/regex_match/ecma/wchar_t/hex.cc:
        Likewise.
        * testsuite/28_regex/algorithms/regex_match/extended/wstring_locale.cc:
        Likewise.
        * testsuite/28_regex/algorithms/regex_search/61720.cc: Likewise.
        * testsuite/28_regex/algorithms/regex_search/ecma/assertion.cc:
        Likewise.
        * testsuite/28_regex/algorithms/regex_search/ecma/string_01.cc:
        Likewise.
        * testsuite/28_regex/basic_regex/ctors/deduction.cc: Likewise.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-11  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/stop_token: Check _GLIBCXX_HAS_GTHREADS using
        #ifdef instead of #if.
        (stop_token::_S_yield()): Check _GLIBCXX_HAS_GTHREADS before
        using __gthread_yield.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-19  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/95765
        * include/bits/stl_algobase.h (__size_to_integer(float))
        (__size_to_integer(double), __size_to_integer(long double))
        (__size_to_integer(__float128)): Cast return type explicitly.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-25  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/17_intro/names.cc: Do not test 'v' on AIX.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-07-30  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/basic_string.h (size_type, difference_type):
        Use allocator_traits to obtain the allocator's size_type and
        difference_type.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-01  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/chrono (duration::_S_gcd(intmax_t, intmax_t)):
        New helper function for finding GCD of two positive intmax_t
        values.
        (duration::__divide): New helper alias for dividing one period
        by another.
        (duration::__is_harmonic): Use __divide not ratio_divide.
        (duration(const duration<R2, P2>&)): Require the duration rep
        types to be convertible.
        * testsuite/20_util/duration/cons/dr2094.cc: New test.
        * testsuite/20_util/duration/requirements/reduced_period.cc:
        Fix definition of unused member functions in test type.
        * testsuite/20_util/duration/requirements/typedefs_neg2.cc:
        Adjust expected errors.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-27  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/chrono (__duration_common_type): Ensure the
        reduced ratio is used. Remove unused partial specialization
        using __failure_type.
        (common_type): Pass reduced ratios to __duration_common_type.
        Add partial specializations for simple cases involving a single
        duration or time_point type.
        (duration::period): Use reduced ratio.
        (duration::operator+(), duration::operator-()): Return duration
        type using the reduced ratio.
        * testsuite/20_util/duration/requirements/typedefs_neg2.cc:
        Adjust expected errors.
        * testsuite/20_util/duration/requirements/reduced_period.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-03  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96592
        * include/std/tuple (_TupleConstraints<true, T...>): Use
        alternative is_constructible instead of std::is_constructible.
        * testsuite/20_util/tuple/cons/96592.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-07-31  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/is_aggregate/value.cc: Adjust for changes to
        definition of aggregates in C++20.
        * testsuite/20_util/optional/requirements.cc: Adjust for
        defaulted comparisons in C++20.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-07-31  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/tuple/78939.cc: Suppress warnings about
        deprecation of volatile-qualified structured bindings in C++20.
        * testsuite/20_util/variable_templates_for_traits.cc: Likewise
        for deprecation of is_pod in C++20

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-09  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/optional (bad_optional_access): Define default
        constructor and destructor as defaulted.
        * testsuite/20_util/optional/bad_access.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-04  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/ranges_algobase.h (__copy_n_fn): Only call
        ranges::copy for positive values.
        * include/bits/stl_algo.h (copy_n): Convert Size argument to an
        integral type and only call __copy_n for positive values.
        * testsuite/util/testsuite_iterators.h
        (random_access_iterator_wrapper::operator+=): Fix range check for
        negative values.
        (output_container, input_container, forward_container)
        (bidirectional_container, random_access_container): New alias
        templates.
        * testsuite/25_algorithms/copy_n/5.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-16  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/atomic (atomic): Add static assertions.
        * testsuite/29_atomics/atomic/requirements/types_neg.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-09  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_iterator.h (move_iterator::operator=): Define.
        * testsuite/24_iterators/move_iterator/dr3265.cc: New test.

2021-03-29  Paul Keir  <paul.keir@uws.ac.uk>

        Backported from master:
        2020-06-15  Paul Keir  <paul.keir@uws.ac.uk>

        * include/bits/char_traits.h (char_traits::move): constexpr move with
        overlap was using copy_backward incorrectly.
        * testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc:
        New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-07-31  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/time_point_cast/rounding.cc: Remove
        duplicate dg-do directive and add c++17 effective target.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-11  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/30_threads/thread/cons/84535.cc: Use a custom
        namespace.
        * testsuite/30_threads/thread/cons/lwg2097.cc: Likewise.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-26  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/lib/libstdc++.exp (libstdc++_init): Only set
        tool_timeout if it hasn't been set by the user already.

2021-03-29  Moritz Sichert  <sichert@in.tum.de>

        Backported from master:
        2021-03-23  Moritz Sichert  <sichert@in.tum.de>

        * include/std/ranges (reverse_view::begin, reverse_view::end):
        Qualify make_reverse_iterator calls to avoid ADL.
        * testsuite/std/ranges/adaptors/reverse.cc: Test that
        views::reverse works when make_reverse_iterator is defined
        in an associated namespace.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-03-22  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/range_access.h (begin(T (&)[N]), end(T (&)[N])):
        Add missing 'noexcept' as per LWG 2280.
        (rbegin(T (&)[N]), rend(T (&)[N]), rbegin(initializer_list<T>))
        (rend(initializer_list<T>)): Add 'noexcept' as per LWG 3537.
        * testsuite/24_iterators/range_access/range_access.cc: Check for
        expected noexcept specifiers. Check result types of generic
        std::begin and std::end overloads.
        * testsuite/24_iterators/range_access/range_access_cpp14.cc:
        Check for expected noexcept specifiers.
        * testsuite/24_iterators/range_access/range_access_cpp17.cc:
        Likewise.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-03-11  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99537
        * include/std/stop_token (_Stop_state_t::_M_release_ownership):
        Use acq_rel memory ordering.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-03-11  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99533
        * src/c++17/fs_dir.cc (recursive_directory_iterator): Use new
        helper function to check for permission denied errors.
        * src/filesystem/dir.cc (recursive_directory_iterator):
        Likewise.
        * src/filesystem/dir-common.h (is_permission_denied_error): New
        helper function.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-03-11  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99536
        * include/bits/random.h (normal_distribution): Use
        default-initializer for _M_saved and _M_saved_available.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-03-10  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/range_cmp.h (__eq_builtin_ptr_cmp): Remove.
        (ranges::equal_to, ranges::not_equal_to): Do not constrain
        with __eq_builtin_ptr_cmp.
        (ranges::less, ranges::greater, ranges::less_equal)
        (ranges::greater_equal): Do not constrain with
        __less_builtin_ptr_cmp.
        * libsupc++/compare (compare_three_way): Do not constrain with
        __3way_builtin_ptr_cmp.
        * testsuite/18_support/comparisons/object/builtin-ptr-three-way.cc: Moved to...
        * testsuite/18_support/comparisons/object/lwg3530.cc: ...here.
        * testsuite/20_util/function_objects/range.cmp/lwg3530.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-12  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/status_cxx2014.xml: Document implementation
        specific properties of std::experimental::filesystem::rename.
        * doc/xml/manual/status_cxx2017.xml: Document implementation
        specific properties of std::filesystem::rename.
        * doc/html/*: Regenerate.
        * src/c++17/fs_ops.cc (fs::rename): Implement correct behaviour
        for directories on Windows.
        * src/filesystem/ops-common.h (__gnu_posix::rename): Use
        MoveFileExW on Windows.
        * testsuite/27_io/filesystem/operations/rename.cc: New test.
        * testsuite/experimental/filesystem/operations/rename.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-12  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/util/testsuite_fs.h (nonexistent_path): Add
        random number to the path.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-12  Jonathan Wakely  <jwakely@redhat.com>

        * include/experimental/internet (address_v6::to_string): Include
        scope ID in string.
        (address_v6::loopback): Fix to be constexpr in C++14.
        * testsuite/experimental/net/internet/address/v6/members.cc:
        Test to_string() results.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-12  Jonathan Wakely  <jwakely@redhat.com>

        * include/experimental/internet (address_v6::any): Avoid using
        memcpy in constexpr function.
        (address_v6::loopback): Likewise.
        (make_address_v6): Fix missing return statements on error paths.
        * include/experimental/io_context: Avoid -Wdangling-else
        warning.
        * testsuite/experimental/net/internet/address/v4/members.cc:
        Remove unused variables.
        * testsuite/experimental/net/internet/address/v6/members.cc:
        New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-29  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/25_algorithms/all_of/constexpr.cc: Check result of
        the algorithm.
        * testsuite/25_algorithms/any_of/constexpr.cc: Likewise.
        * testsuite/25_algorithms/binary_search/constexpr.cc: Likewise.
        * testsuite/25_algorithms/copy_backward/constexpr.cc: Likewise.
        * testsuite/25_algorithms/count/constexpr.cc: Likewise.
        * testsuite/25_algorithms/equal/constexpr.cc: Likewise.
        * testsuite/25_algorithms/equal_range/constexpr.cc: Likewise.
        * testsuite/25_algorithms/fill/constexpr.cc: Likewise.
        * testsuite/25_algorithms/find_end/constexpr.cc: Likewise.
        * testsuite/25_algorithms/find_if/constexpr.cc: Likewise.
        * testsuite/25_algorithms/is_partitioned/constexpr.cc: Likewise.
        * testsuite/25_algorithms/is_permutation/constexpr.cc: Likewise.
        * testsuite/25_algorithms/is_sorted_until/constexpr.cc:
        Likewise.
        * testsuite/25_algorithms/lexicographical_compare/constexpr.cc:
        Likewise.
        * testsuite/25_algorithms/lower_bound/constexpr.cc: Likewise.
        * testsuite/25_algorithms/merge/constexpr.cc: Likewise.
        * testsuite/25_algorithms/mismatch/constexpr.cc: Likewise.
        * testsuite/25_algorithms/none_of/constexpr.cc: Likewise.
        * testsuite/25_algorithms/partition_copy/constexpr.cc: Likewise.
        * testsuite/25_algorithms/remove_copy/constexpr.cc: Likewise.
        * testsuite/25_algorithms/remove_copy_if/constexpr.cc: Likewise.
        * testsuite/25_algorithms/remove_if/constexpr.cc: Likewise.
        * testsuite/25_algorithms/replace_if/constexpr.cc: Likewise.
        * testsuite/25_algorithms/reverse/constexpr.cc: Likewise.
        * testsuite/25_algorithms/reverse_copy/constexpr.cc: Likewise.
        * testsuite/25_algorithms/rotate_copy/constexpr.cc: Likewise.
        * testsuite/25_algorithms/search/constexpr.cc: Likewise.
        * testsuite/25_algorithms/set_difference/constexpr.cc: Likewise.
        * testsuite/25_algorithms/set_intersection/constexpr.cc:
        Likewise.
        * testsuite/25_algorithms/set_symmetric_difference/constexpr.cc:
        Likewise.
        * testsuite/25_algorithms/set_union/constexpr.cc: Likewise.
        * testsuite/25_algorithms/unique_copy/constexpr.cc: Likewise.
        * testsuite/25_algorithms/upper_bound/constexpr.cc: Likewise.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-12  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99077
        * src/c++11/cxx11-ios_failure.cc (__ios_failure(const char*, int)):
        Change int parameter to error_code, to match std::ios_failure.
        (__throw_ios_failure(const char*, int)): Construct error_code
        from int parameter.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-11  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99058
        * doc/xml/manual/status_cxx2011.xml: Document when support
        became stable.
        * doc/xml/manual/status_cxx2014.xml: Likewise.
        * doc/xml/manual/status_cxx2017.xml: Likewise.
        * doc/html/manual/status.html: Regenerate.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-12  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/88881
        * src/c++17/fs_ops.cc (fs::symlink_status): Re-enable workaround.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/88881
        * src/c++17/fs_ops.cc (fs::status): Re-enable workaround.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-10  Jonathan Wakely  <jwakely@redhat.com>

        * src/c++17/fs_ops.cc (fs::create_hard_link, fs::equivalent)
        (fs::remove): Use std::system_category() for error codes from
        GetLastError().
        * src/filesystem/ops.cc (fs::create_hard_link, fs::remove):
        Likewise.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-10  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/27_io/filesystem/operations/proximate.cc: Fix typo
        in __MINGW32__ macro name.
        * testsuite/27_io/filesystem/path/compare/lwg2936.cc: Likewise.
        * testsuite/27_io/filesystem/path/generation/proximate.cc:
        Likewise.
        * testsuite/27_io/filesystem/path/generation/relative.cc:
        Likewise.
        * testsuite/util/testsuite_fs.h: Likewise.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-03  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/19_diagnostics/error_code/operators/not_equal.cc:
        Add comparison with same category and different values.
        * testsuite/19_diagnostics/error_code/operators/less.cc:
        Likewise. Fix comparison involving different categories.
        * testsuite/19_diagnostics/error_code/operators/three_way.cc:
        Likewise.
        * testsuite/19_diagnostics/error_condition/operators/less.cc:
        Add comment.
        * testsuite/19_diagnostics/error_condition/operators/three_way.cc:
        Likewise.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-12-16  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/98319
        * include/experimental/random: Only define contents for C++14
        and later.
        * include/experimental/source_location: Likewise.
        * include/experimental/utility: Likewise.
        * testsuite/experimental/feat-lib-fund.cc: Include all LFTS
        headers that are present. Allow test to run for all modes.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-12-16  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93151
        * acinclude.m4 (GLIBCXX_CHECK_SYSTEM_ERROR): Remove.
        * configure.ac: Regenerate.
        * config/os/generic/error_constants.h: Test POSIX errno macros
        directly, instead of corresponding _GLIBCXX_HAVE_EXXX macros.
        * testsuite/19_diagnostics/headers/system_error/errc_std_c++0x.cc:
        Likewise.
        * testsuite/19_diagnostics/headers/system_error/93151.cc: New
        test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-12-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/98226
        * include/std/bit (__countl_one, __countr_one): Remove redundant
        branches.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-09  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/bit (__popcount): Remove redundant check for zero.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-30  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (enable_borrowed_view<take_view<T>>)
        (enable_borrowed_view<drop_view<T>>)
        (enable_borrowed_view<drop_while_view<T>>)
        (enable_borrowed_view<reverse_view<T>>)
        (enable_borrowed_view<common_view<T>>)
        (enable_borrowed_view<elements_view<T>>): Add partial
        specializations as per P2017R1.
        * testsuite/std/ranges/adaptors/conditionally_borrowed.cc:
        New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-29  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (subrange::subrange(R&&)): Use
        direct-initialization instead of list-initialization, so a
        potential narrowing conversion from ranges::size(r) to the
        stored size isn't ill-formed.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-08  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/82584
        * include/bits/random.tcc
        (discrete_distribution::param_type::_M_initialize)
        (piecewise_constant_distribution::param_type::_M_initialize)
        (piecewise_linear_distribution::param_type::_M_initialize):
        Add assertions for positive sums..
        * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
        line.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-08  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/random.h (__detail::_Mod): Revert last change.
        (__detail::__mod): Do not use _Mod for a==0 case.
        * testsuite/26_numerics/random/linear_congruential_engine/operators/call.cc:
        Check other cases with a==0. Also check runtime results.
        * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
        line.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-07  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/random.h (__detail::_Mod): Avoid divide by zero.
        * testsuite/26_numerics/random/linear_congruential_engine/operators/call.cc:
        New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-21  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (drop_view::begin()): Adjust constraints
        to match the correct condition for O(1) ranges::next (LWG 3482).
        * testsuite/std/ranges/adaptors/drop.cc: Check that iterator is
        cached for non-sized_range.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-21  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (transform_view, elements_view): Relax
        constraints on operator- for iterators, as per LWG 3483.
        * testsuite/std/ranges/adaptors/elements.cc: Check that we
        can take the difference of two iterators from a non-random
        access range.
        * testsuite/std/ranges/adaptors/transform.cc: Likewise.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-28  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/95592
        * include/bits/valarray_after.h (_DEFINE_EXPR_UNARY_OPERATOR)
        (_DEFINE_EXPR_BINARY_OPERATOR, _DEFINE_EXPR_BINARY_FUNCTION):
        Use elaborated-type-specifier and qualified-id to avoid
        ambiguities with QNX system headers.
        * testsuite/26_numerics/valarray/95592.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-27  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/locale_conv.h (__str_codecvt_out_all):
        Add cast to compare operands of the same signedness.
        * include/bits/locale_facets_nonio.tcc
        (time_get::_M_extract_wday_or_month): Likewise.
        * include/bits/sstream.tcc (basic_stringbuf::overflow):
        Likewise.
        * include/tr1/legendre_function.tcc (__sph_legendre): Use
        unsigned for loop variable.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-10  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/locale_conv.h (__do_str_codecvt, __str_codecvt_in_all):
        Add casts to compare types of the same signedness.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-10  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/ranges_algobase.h (__equal_fn): Remove unused
        typedef.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-10  Jonathan Wakely  <jwakely@redhat.com>

        * include/experimental/bits/shared_ptr.h (shared_ptr(auto_ptr&&))
        (operator=(auto_ptr&&)): Add diagnostic pragmas to suppress
        warnings for uses of std::auto_ptr.
        * include/experimental/type_traits (is_literal_type_v):
        Likewise, for use of std::is_literal_type.
        * include/std/condition_variable (condition_variable_any::_Unlock):
        Likewise, for use of std::uncaught_exception.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-10  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/fs_path.h (path::_List::type()): Avoid narrowing
        conversion.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-07  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (__box): Simplify constraints as per LWG 3477.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-24  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (ranges::iota_view::size()): Perform all
        calculations in the right unsigned types.
        * testsuite/std/ranges/iota/size.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-11  Jonathan Wakely  <jwakely@redhat.com>

        * include/experimental/executor (system_context::_M_run()):
        Fix predicate.
        (system_context::join()): Do not join unless joinable.
        * testsuite/experimental/net/system_context/1.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-10  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_iterator.h (inserter): Do not deduce
        iterator type (LWG 561).
        * testsuite/24_iterators/insert_iterator/dr561.cc: New test.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-27  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/fs_path.h (path::_List::begin, path::_List::end):
        Add noexcept to match definitions in src/c++17/fs_path.cc.

2021-03-29  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-27  Jonathan Wakely  <jwakely@redhat.com>

        * src/c++17/fs_dir.cc (fs::directory_iterator::operator*):
        Add noexcept. Do not throw on precondition violation.

2021-03-19  Jakub Jelinek  <jakub@redhat.com>

        Backported from master:
        2021-02-23  Jakub Jelinek  <jakub@redhat.com>

        PR libstdc++/99181
        * testsuite/21_strings/char_traits/requirements/char/99181.cc: New
        test.

2021-03-19  Jakub Jelinek  <jakub@redhat.com>

        Backported from master:
        2021-02-23  Jakub Jelinek  <jakub@redhat.com>

        PR libstdc++/99181
        * include/bits/char_traits.h (char_traits<char>::compare): For
        constexpr evaluation don't call
        __gnu_cxx::char_traits<char_type>::compare but do the comparison loop
        directly.

2021-02-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2021-02-09  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/99021
        * include/std/coroutine (coroutine_handle<P>::from_address): Add
        noexcept.

2021-01-13  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/98605
        * include/std/mutex (call_once): Use NOLINT to suppress clang
        analyzer warnings.

2021-01-11  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-12-02  Jonathan Wakely  <jwakely@redhat.com>

        * python/libstdcxx/v6/printers.py (StdExpPathPrinter): Store the
        name of the type and pass it to the iterator.
        (StdPathPrinter): Likewise.
        * testsuite/libstdc++-prettyprinters/filesystem-ts.cc: New test.

2021-01-11  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-12-16  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96083
        * include/ext/throw_allocator.h: Use __has_builtin to check for
        __builtin_sprintf support, and use std::sprintf if necessary.

2021-01-11  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-12-02  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/65480
        PR libstdc++/68735
        * python/libstdcxx/v6/printers.py (function_pointer_to_name):
        New helper function to get the name of a function from its
        address.
        (StdExpAnyPrinter.__init__): Use it.

2021-01-11  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-07-31  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/experimental/filesystem/filesystem_error/cons.cc:
        Remove -std=gnu++17 option.

2021-01-08  Iain Sandoe  <iain@sandoe.co.uk>

        Backported from master:
        2020-07-17  Iain Sandoe  <iain@sandoe.co.uk>

        * include/std/coroutine: Mark the methods of the
        trivial awaitables as constexpr.

2021-01-03  Iain Sandoe  <iain@sandoe.co.uk>
            Jakub Jelinek   <jakub@redhat.com>

        PR target/97865
        * configure: Regenerate.

2020-12-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-12-03  Jonathan Wakely  <jwakely@redhat.com>

        * config/abi/post/powerpc-linux-gnu/baseline_symbols.txt:
        Update.
        * config/abi/post/powerpc64-linux-gnu/32/baseline_symbols.txt:
        Update.

2020-12-01  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-10-12  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/95322
        * include/std/ranges (take_view::_CI): Define this alias
        template as per LWG 3449 and remove ...
        (take_view::_Sentinel::_CI): ... this type alias.
        (take_view::_Sentinel::operator==): Adjust use of _CI
        accordingly.  Define a second overload that accepts an iterator
        of the opposite constness as per LWG 3449.
        (take_while_view::_Sentinel::operator==): Likewise.
        * testsuite/std/ranges/adaptors/95322.cc: Add tests for LWG 3449.

2020-11-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-26  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/98001
        * testsuite/ext/stdio_filebuf/char/79820.cc: Do not pass invalid
        FILE* to constructor.

2020-11-25  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-25  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97935
        * include/bits/iterator_concepts.h (__detail::__iter_without_category):
        New helper concept.
        (__iterator_traits::__cat): Use __detail::__iter_without_category.
        * testsuite/24_iterators/associated_types/iterator.traits.cc: New test.

2020-11-25  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-04  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/iterator_concepts.h (__detail::__ptr, __detail::__ref)
        (__detail::__cat, __detail::__diff): Move to class scope in the
        relevant __iterator_traits specializations.
        (__iterator_traits<>): Use nested class templates instead of ones from
        namespace __detail.
        * include/bits/stl_iterator.h (__detail::__common_iter_ptr): Move to
        class scope in iterator_traits<common_iterator<I, S>>.
        (iterator_traits<common_iterator<I, S>>): Use nested class template
        instead of __detail::__common_iter_ptr.

2020-11-24  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-02  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/29_atomics/atomic_float/value_init.cc: Use float
        instead of double so that __atomic_load_8 isn't needed.

2020-11-20  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-20  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/92546
        * include/std/regex (pmr::smatch, pmr::wsmatch): Declare using
        underlying __normal_iterator type, not nested typedef
        basic_string::const_iterator.

2020-11-20  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97876
        * include/std/stop_token (_Stop_state_t): Define default
        constructor as user-provided not defaulted.

2020-11-20  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-19  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/95989
        * config/os/gnu-linux/os_defines.h (_GLIBCXX_NATIVE_THREAD_ID):
        Define new macro to get reliable thread ID.
        * include/std/stop_token (_Stop_state_t::_M_request_stop):
        Use new macro if it's defined.
        (_Stop_state_t::_M_remove_callback): Likewise.
        * include/std/thread (this_thread::get_id): Likewise.
        * testsuite/30_threads/jthread/95989.cc: New test.
        * testsuite/30_threads/this_thread/95989.cc: New test.

2020-11-18  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-11-18  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (join_view::_Iterator::_M_satisfy): Uglify
        local variable inner.
        (join_view::_Iterator::operator->): Use _Inner_iter instead of
        _Outer_iter in the function signature as per LWG 3500.
        * testsuite/std/ranges/adaptors/join.cc (test08): Test it.

2020-11-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-06  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (join_view): Remove deduction guide.
        (views::join): Add explicit template argument list to prevent
        deducing the wrong type.
        * testsuite/std/ranges/adaptors/join.cc: Move test for LWG 3474
        here, from ...
        * testsuite/std/ranges/adaptors/join_lwg3474.cc: Removed.

2020-11-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-24  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (join_view): Add deduction guide (LWG 3474).
        * testsuite/std/ranges/adaptors/join_lwg3474.cc: New test.

2020-11-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-10  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/version (__cpp_lib_array_constexpr)
        (__cpp_lib_constexpr_char_traits): Only define C++17 value when
        compiling C++17.

2020-11-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-15  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/char_traits.h (__cpp_lib_constexpr_char_traits):
        Update value for C++20.
        * include/std/version (__cpp_lib_constexpr_char_traits): Likewise.
        * testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc:
        Update expected value.

2020-11-18  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-17  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97869
        * include/precompiled/stdc++.h: Include <coroutine>.
        * include/std/version (__cpp_lib_span): Check __cpp_lib_concepts
        before defining.

2020-11-17  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-11-17  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/97828
        * include/bits/ranges_algo.h (__search_n_fn::operator()): Check
        random_access_iterator before using the backtracking
        implementation.  When the backwards scan fails prematurely,
        reset __remainder appropriately.
        * testsuite/25_algorithms/search_n/97828.cc: New test.

2020-11-16  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-13  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93456
        * src/c++11/futex.cc (relative_timespec): Remove redundant check
        negative values.
        * testsuite/30_threads/future/members/93456.cc: New.

2020-11-16  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-16  Jonathan Wakely  <jwakely@redhat.com>

        * src/c++11/futex.cc (relative_timespec): New function to
        create relative time from two absolute times.
        (__atomic_futex_unsigned_base::_M_futex_wait_until): Use
        relative_timespec.

2020-11-16  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-12  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/future (future::wait_for): Do not wait for
        durations less than or equal to zero.
        * testsuite/30_threads/future/members/poll.cc: New test.

2020-11-13  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-13  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97798
        * include/ext/numeric_traits.h (__glibcxx_signed)
        (__glibcxx_digits, __glibcxx_min, __glibcxx_max): Remove
        macros.
        (__is_integer_nonstrict::__width): Define new constant.
        (__numeric_traits_integer): Define constants in terms of each
        other and __is_integer_nonstrict::__width, rather than the
        removed macros.
        (_GLIBCXX_INT_N_TRAITS): Macro to define explicit
        specializations for non-standard integer types.

2020-11-13  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96042
        * testsuite/std/ranges/iota/96042.cc: Only assert that the
        difference type is wider than long long if __int128 is
        supported.

2020-11-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-20  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/iterator_concepts.h [__STRICT_ANSI__]
        (incrementable_traits<__int128>): Define specialization.
        (incrementable_traits<unsigned __int128>): Likewise.
        * testsuite/std/ranges/iota/96042.cc: Test iota_view with
        __int128.

2020-11-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-19  Jonathan Wakely  <jwakely@redhat.com>
                    Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/96042
        * include/bits/range_access.h (__detail::__to_unsigned_like):
        Do not use make_unsigned_t<T> in the return type, as it can
        result in an error before the integral<T> constraint is checked.
        [__STRICT_ANSI__]: Add overloads for 128-bit integer types.
        (__detail::__make_unsigned_like_t): Define as the return type
        of __to_unsigned_like.
        * testsuite/std/ranges/subrange/96042.cc: New test.

2020-11-12  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-19  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96042
        * include/ext/numeric_traits.h (__is_integer_nonstrict): New
        trait which is true for 128-bit integers even in strict modes.
        (__numeric_traits_integer, __numeric_traits): Use
        __is_integer_nonstrict instead of __is_integer.
        * include/std/limits [__STRICT_ANSI__ && __SIZEOF_INT128__]
        (numeric_limits<__int128>, (numeric_limits<unsigned __int128>):
        Define.
        * testsuite/std/ranges/iota/96042.cc: New test.

2020-11-11  Paul Scharnofske  <asynts@gmail.com>

        Backported from master:
        2020-11-11  Paul Scharnofske  <asynts@gmail.com>

        * include/std/thread (jthread::operator=(jthread&&)): Transfer
        any existing state to a temporary that will request a stop and
        then join.
        * testsuite/30_threads/jthread/jthread.cc: Test move assignment.

2020-11-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-05  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96269
        * include/std/optional (operator==, operator!=, operator<)
        (operator>, operator<=, operator>=): Fix types used in
        SFINAE constraints.
        * testsuite/20_util/optional/relops/96269.cc: New test.

2020-11-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-05  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97731
        * src/filesystem/dir.cc (recursive_directory_iterator): Call the
        right overload of _Dir::advance.
        * testsuite/experimental/filesystem/iterators/97731.cc: New test.

2020-11-05  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97362
        * doc/html/manual/source_code_style.html: Regenerate.
        * doc/xml/manual/appendix_contributing.xml: Add __deref to
        BADNAMES.
        * include/debug/functions.h (_Irreflexive_checker::__deref):
        Rename to __ref.
        * testsuite/17_intro/badnames.cc: Check __deref.

2020-11-04  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-11-04  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/92285
        * doc/xml/manual/evolution.xml: Document change to base class.
        * doc/html/manual/api.html: Regenerate.

2020-11-04  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/evolution.xml: Document new C++20 headers.
        * doc/html/*: Regenerate.

2020-11-04  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-01  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/evolution.xml: Document deprecation of
        __is_nullptr_t and removal of std::allocator members.
        * doc/html/manual/api.html: Regenerate.

2020-11-04  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-01  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/containers.xml: Replace <xref> with <link>.
        * doc/xml/manual/evolution.xml: Likewise.
        * doc/html/manual/api.html: Regenerate.
        * doc/html/manual/containers.html: Regenerate.

2020-10-29  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-10-29  Patrick Palka  <ppalka@redhat.com>

        * testsuite/25_algorithms/lexicographical_compare/constrained.cc:
        (test03): Fix initializing the vector vy with the array y of size 4.

2020-10-28  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-10-23  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (single_view::single_view): Mark the
        in place constructor explicit as per LWG 3428.
        (take_view): Remove the constraint on the deduction guide's
        template parameter as per LWG 3447.

2020-10-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-09-22  Patrick Palka  <ppalka@redhat.com>

        * include/std/span (span::front): Remove static_assert.
        (span::back): Likewise.
        (span::operator[]): Likewise.
        * testsuite/23_containers/span/back_neg.cc: Rewrite to verify
        that we check the preconditions of back() only when it's called.
        * testsuite/23_containers/span/front_neg.cc: Likewise for
        front().
        * testsuite/23_containers/span/index_op_neg.cc: Likewise for
        operator[].

2020-10-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-10-12  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (take_while_view::begin): Constrain the
        const overload further as per LWG 3450.
        (take_while_view::end): Likewise.
        * testsuite/std/ranges/adaptors/take_while.cc: Add test for LWG
        3450.

2020-10-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-09-22  Patrick Palka  <ppalka@redhat.com>

        * include/bits/stl_algo.h (__sample): Exit early when the
        input range is empty.
        * testsuite/25_algorithms/sample/3.cc: New test.

2020-10-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-09-22  Patrick Palka  <ppalka@redhat.com>

        * include/bits/stl_algo.h (for_each_n): Mark constexpr for C++20.
        (search): Likewise for the overload that takes a searcher.
        * testsuite/25_algorithms/for_each/constexpr.cc: Test constexpr
        std::for_each_n.
        * testsuite/25_algorithms/search/constexpr.cc: Test constexpr
        std::search overload that takes a searcher.

2020-10-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-08-27  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/95322
        * include/std/ranges (transform_view::sentinel::__distance_from):
        Give this a deduced return type.
        (transform_view::sentinel::operator-): Adjust the return type so
        that it's based on the constness of the iterator rather than
        that of the sentinel.
        * testsuite/std/ranges/adaptors/95322.cc: Refer to LWG 3488.

2020-10-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-08-27  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (elements_view::begin): Adjust constraints.
        (elements_view::end): Likewise.
        (elements_view::_Sentinel::operator==): Templatize to take both
        _Iterator<true> and _Iterator<false>.
        (elements_view::_Sentinel::operator-): Likewise.
        * testsuite/std/ranges/adaptors/elements.cc: Add testcase for
        the example from P1994R1.
        * testsuite/std/ranges/adaptors/lwg3406.cc: New test.

2020-10-21  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-08-27  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (elements_view::end): Replace these two
        overloads with four new overloads.
        (elements_view::_Iterator::operator==): Remove.
        (elements_view::_Iterator::operator-): Likewise.
        (elements_view::_Sentinel): Define.

2020-10-20  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-10  Jonathan Wakely  <jwakely@redhat.com>

        * python/libstdcxx/v6/printers.py (UniquePointerPrinter.__init__):
        Use gdb.Type.strip_typedefs().
        * testsuite/libstdc++-prettyprinters/compat.cc: Use a typedef in
        the emulated old type.

2020-10-20  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-14  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/basic_string.h [!_GLIBCXX_USE_CXX11_ABI]
        (basic_string(const _CharT*, const _Alloc&)): Constrain to
        require an allocator-like type to fix CTAD ambiguity (LWG 3706).
        Define inline.
        * include/bits/basic_string.tcc [!_GLIBCXX_USE_CXX11_ABI]
        (basic_string(const _CharT*, const _Alloc&)): Remove non-inline
        definition.
        * testsuite/21_strings/basic_string/cons/char/deduction.cc:
        Remove dg-skip-if.
        * testsuite/21_strings/basic_string/cons/wchar_t/deduction.cc:
        Likewise.

2020-10-20  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-14  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/21_strings/basic_string/allocator/char/minimal.cc:
        Do not require cxx11-abi effective target.
        * testsuite/21_strings/basic_string/allocator/wchar_t/minimal.cc:
        Likewise.
        * testsuite/27_io/basic_fstream/cons/base.cc: Likewise.

2020-10-20  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-08  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/ios_base.h (ios_base::failure): Add constructors
        takeing error_code argument. Add code() member function.
        * testsuite/27_io/ios_base/failure/cxx11.cc: Allow test to
        run for the old ABI but do not check for derivation from
        std::system_error.
        * testsuite/27_io/ios_base/failure/error_code.cc: New test.

2020-10-20  Nuno Lopes  <nuno.lopes@ist.utl.pt>

        Backported from master:
        2020-10-13  Nuno Lopes  <nuno.lopes@ist.utl.pt>

        * include/bits/stl_algo.h (any_of): Fix incorrect description
        in comment.

2020-10-20  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-12  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_algobase.h (copy, move, copy_backward)
        (move_backward): Fix documentation for returned iterator.

2020-10-20  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-24  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/configure.xml: Correct name of option.
        * doc/html/*: Regenerate.

2020-10-19  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-21  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97132
        * include/std/memory (assume_aligned): Do not use
        __builtin_assume_aligned during constant evaluation.
        * testsuite/20_util/assume_aligned/1.cc: Improve test.
        * testsuite/20_util/assume_aligned/97132.cc: New test.

2020-10-15  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-15  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/concepts: Fix typos in copyright notice.
        * include/std/ranges: Likewise.

2020-10-15  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/status_cxx2020.xml: Remove red background for
        completed feature.
        * doc/html/manual/status.html: Regenerate.

2020-10-13  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-10-08  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/95788
        * include/bits/ranges_uninitialized.h:
        (__construct_at_fn::operator()): Rewrite in terms of
        std::construct_at.  Declare it conditionally noexcept.  Qualify
        calls to declval in its requires-clause.
        * testsuite/20_util/specialized_algorithms/construct_at/95788.cc:
        New test.

2020-10-08  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-10-07  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/random.h (seed_seq(initializer_list<T>)): Rename
        parameter to use reserved name.
        * include/bits/ranges_algo.h (shift_left, shift_right): Rename
        template parameters to use reserved name.
        * testsuite/17_intro/names.cc: Check "il". Do not check "d" and
        "y" in C++20 mode.

2020-10-06  Patrick Palka  <ppalka@redhat.com>

        Backported from master:
        2020-10-02  Patrick Palka  <ppalka@redhat.com>

        * include/bits/stl_iterator.h (reverse_iterator::iter_move):
        Define for C++20 as per P0896.
        (reverse_iterator::iter_swap): Likewise.
        (move_iterator::operator*): Apply P0896 changes for C++20.
        (move_iterator::operator[]): Likewise.
        * testsuite/24_iterators/reverse_iterator/cust.cc: New test.

2020-09-22  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-22  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97167
        * src/c++17/fs_path.cc (path::_Parser::root_path()): Check
        for empty string before inspecting the first character.
        * testsuite/27_io/filesystem/path/append/source.cc: Append
        empty string_view to path.

2020-09-22  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-22  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96803
        * include/std/tuple
        (_Tuple_impl(allocator_arg_t, Alloc, const _Tuple_impl<U...>&)):
        Use correct value category in __use_alloc call.
        * testsuite/20_util/tuple/cons/96803.cc: Check with constructors
        that require correct value category to be used.

2020-09-22  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-26  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96803
        * include/std/tuple
        (_Tuple_impl(allocator_arg_t, Alloc, const _Tuple_impl<U...>&)):
        Replace parameter pack with a type parameter and a pack and pass
        the first type to __use_alloc.
        * testsuite/20_util/tuple/cons/96803.cc: New test.

2020-09-21  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94681
        * src/c++17/fs_ops.cc (read_symlink): Use posix::lstat instead
        of calling ::lstat directly.
        * src/filesystem/ops.cc (read_symlink): Likewise.

2020-09-21  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94681
        * acinclude.m4 (GLIBCXX_CHECK_FILESYSTEM_DEPS): Do not depend on
        $enable_libstdcxx_filesystem_ts.
        * configure: Regenerate.

2020-09-21  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-20  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/97101
        * include/std/functional (bind_front): Fix order of parameters
        in is_nothrow_constructible_v specialization.
        * testsuite/20_util/function_objects/bind_front/97101.cc: New test.

2020-09-21  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94160
        * src/c++17/memory_resource.cc (munge_options): Round
        max_blocks_per_chunk to a multiple of four.
        (__pool_resource::_M_alloc_pools()): Simplify slightly.
        * testsuite/20_util/unsynchronized_pool_resource/allocate.cc:
        Check that valid pointers are returned when small values are
        used for max_blocks_per_chunk.

2020-09-03  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-07-07  Jonathan Wakely  <jwakely@redhat.com>

        * include/Makefile.am: Remove bits/int_limits.h.
        * include/Makefile.in: Regenerate.
        * include/bits/int_limits.h: Removed.
        * include/bits/parse_numbers.h (_Select_int_base): Replace
        __int_limits with __int_traits.
        * include/bits/range_access.h (_SSize::operator()): Likewise.
        * include/ext/numeric_traits.h (__numeric_traits_integer): Add
        static assertion.
        (__int_traits): New alias template.
        * include/std/bit (__rotl, __rotr, __countl_zero, __countl_one)
        (__countr_zero, __countr_one, __popcount, __bit_ceil)
        (__bit_floor, __bit_width) Replace __int_limits with
        __int_traits.
        * include/std/charconv (__to_chars_8, __from_chars_binary)
        (__from_chars_alpha_to_num, from_chars): Likewise.
        * include/std/memory_resource (polymorphic_allocator::allocate)
        (polymorphic_allocator::allocate_object): Likewise.
        * include/std/string_view (basic_string_view::_S_compare):
        Likewise.
        * include/std/utility (cmp_equal, cmp_less, in_range): Likewise.

2020-09-02  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-28  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/92978
        * include/std/numeric (__abs_integral): Replace with ...
        (__detail::__absu): New function template that returns an
        unsigned type, guaranteeing it can represent the most
        negative signed value.
        (__detail::__gcd, __detail::__lcm): Require arguments to
        be unsigned and therefore already non-negative.
        (gcd, lcm): Convert arguments to absolute value as unsigned
        type before calling __detail::__gcd or __detail::__lcm.
        * include/experimental/numeric (gcd, lcm): Likewise.
        * testsuite/26_numerics/gcd/gcd_neg.cc: Adjust expected
        errors.
        * testsuite/26_numerics/lcm/lcm_neg.cc: Likewise.
        * testsuite/26_numerics/gcd/92978.cc: New test.
        * testsuite/26_numerics/lcm/92978.cc: New test.
        * testsuite/experimental/numeric/92978.cc: New test.

2020-09-02  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-09-02  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96851
        * include/bits/cpp_type_traits.h (__is_memcmp_ordered):
        New trait that says if memcmp can be used for ordering.
        (__is_memcmp_ordered_with): Likewise, for two types.
        * include/bits/ranges_algo.h (__lexicographical_compare_fn):
        Use new traits instead of __is_byte and __numeric_traits.
        * include/bits/stl_algobase.h (__lexicographical_compare_aux1)
        (__is_byte_iter): Likewise.
        * include/std/array (operator<=>): Likewise. Only use memcmp
        when std::is_constant_evaluated() is false.
        * testsuite/23_containers/array/comparison_operators/96851.cc:
        New test.
        * testsuite/23_containers/array/tuple_interface/get_neg.cc:
        Adjust dg-error line numbers.

2020-09-02  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_iterator.h (counted_iterator::operator++(int)):
        Use __throw_exception_again macro.

2020-08-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-26  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/71960
        * include/experimental/string_view (basic_string_view):
        Enable debug assertions.
        * include/std/string_view (basic_string_view):
        Likewise.

2020-08-26  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-24  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96766
        * include/std/variant (_Variant_storage): Replace implicit
        conversions from size_t to __index_type with explicit casts.

2020-08-21  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-21  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96718
        * testsuite/25_algorithms/pstl/feature_test-2.cc: Require
        tbb-backend effective target.
        * testsuite/25_algorithms/pstl/feature_test-3.cc: Likewise.
        * testsuite/25_algorithms/pstl/feature_test-5.cc: Likewise.
        * testsuite/25_algorithms/pstl/feature_test.cc: Likewise.

2020-08-19  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-19  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/c++config (_GLIBCXX_DEPRECATED_SUGGEST): New
        macro for "use 'foo' instead" message in deprecated warnings.
        * include/bits/ios_base.h (io_state, open_mode, seek_dir)
        (streampos, streamoff): Use _GLIBCXX_DEPRECATED_SUGGEST.
        * include/std/streambuf (stossc): Replace C++11 attribute
        with _GLIBCXX_DEPRECATED_SUGGEST.
        * include/std/type_traits (__is_nullptr_t): Use
        _GLIBCXX_DEPRECATED_SUGGEST instead of _GLIBCXX_DEPRECATED.
        * testsuite/27_io/types/1.cc: Check for deprecated warnings.
        Also check for io_state, open_mode and seek_dir typedefs.

2020-08-11  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/89760
        * testsuite/experimental/net/execution_context/make_service.cc:
        Add dg-require-gthreads.
        * testsuite/experimental/net/executor/1.cc: Likewise.
        * testsuite/experimental/net/headers.cc: Likewise.
        * testsuite/experimental/net/internet/address/v4/comparisons.cc:
        Likewise.
        * testsuite/experimental/net/internet/address/v4/cons.cc:
        Likewise.
        * testsuite/experimental/net/internet/address/v4/creation.cc:
        Likewise.
        * testsuite/experimental/net/internet/address/v4/members.cc:
        Likewise.
        * testsuite/experimental/net/internet/resolver/base.cc:
        Likewise.
        * testsuite/experimental/net/internet/resolver/ops/lookup.cc:
        Likewise.
        * testsuite/experimental/net/internet/resolver/ops/reverse.cc:
        Likewise.
        * testsuite/experimental/net/socket/basic_socket.cc: Likewise.
        * testsuite/experimental/net/timer/waitable/cons.cc: Likewise.
        * testsuite/experimental/net/timer/waitable/dest.cc: Likewise.
        * testsuite/experimental/net/timer/waitable/ops.cc: Likewise.

2020-08-10  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-10  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/95749
        * src/filesystem/ops-common.h [_GLIBCXX_FILESYSTEM_IS_WINDOWS]
        (stat_type): Change to __stat64.
        (stat): Use _wstat64.

2020-08-07  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-07  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96303
        * include/debug/bitset (bitset::operator==): Call _M_base() on
        right operand.
        (bitset::operator!=): Likewise, but don't define it at all when
        default comparisons are supported by the compiler.
        * testsuite/23_containers/bitset/operations/96303.cc: New test.

2020-08-06  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-08-06  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/96484
        * src/c++17/fs_ops.cc (fs::read_symlink): Return an error
        immediately for non-symlinks.
        * src/filesystem/ops.cc (fs::read_symlink): Likewise.

2020-07-23  Release Manager

        * GCC 10.2.0 released.

2020-07-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-08  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/unique_ptr.h (operator<<): Define for C++20.
        * testsuite/20_util/unique_ptr/io/lwg2948.cc: New test.
        * testsuite/20_util/default_delete/48631_neg.cc: Adjust dg-error
        line number.
        * testsuite/20_util/default_delete/void_neg.cc: Likewise.

2020-07-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-05-27  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/95322
        * include/std/ranges (transform_view::_Sentinel): Allow hidden
        friends to work with _Iterator<true> and _Iterator<false>.
        (join_view::_Sentinel): Likewise.
        * testsuite/std/ranges/adaptors/95322.cc: New test.

2020-07-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-05-04  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94936
        * src/c++17/memory_resource.cc (synchronized_pool_resource::_TPools):
        Add comment about single-threaded behaviour.
        (synchronized_pool_resource::_TPools::move_nonempty_chunks()): Hoist
        class member access out of loop.
        (synchronized_pool_resource::synchronized_pool_resource())
        (synchronized_pool_resource::~synchronized_pool_resource())
        (synchronized_pool_resource::release()): Check __gthread_active_p
        before creating and/or deleting the thread-specific data key.
        (synchronized_pool_resource::_M_thread_specific_pools()): Adjust
        assertions.
        (synchronized_pool_resource::do_allocate(size_t, size_t)): Add fast
        path for single-threaded case.
        (synchronized_pool_resource::do_deallocate(void*, size_t, size_t)):
        Likewise. Return if unable to find a pool that owns the allocation.
        * testsuite/20_util/synchronized_pool_resource/allocate_single.cc:
        New test.
        * testsuite/20_util/synchronized_pool_resource/cons_single.cc: New
        test.
        * testsuite/20_util/synchronized_pool_resource/release_single.cc: New
        test.

2020-07-09  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-05-19  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94087
        * src/c++11/random.cc (__x86_rdseed): Allow fallback function to be
        passed in.
        (__x86_rdseed_rdrand): New function that uses rdseed with rdrand
        fallback.
        (random_device::_M_init): Use __x86_rdseed_rdrand when both
        instructions are available.
        * testsuite/26_numerics/random/random_device/94087.cc: New test.

2020-07-02  Ville Voutilainen  <ville.voutilainen@gmail.com>

        Backported from master:
        2020-07-02  Ville Voutilainen  <ville.voutilainen@gmail.com>

        PR libstdc++/91807
        * include/std/variant
        (_Copy_assign_base::operator=(const _Copy_assign_base&):
        Do the move-assignment from a temporary so that the temporary
        is constructed with an explicit index.
        * testsuite/20_util/variant/91807.cc: New.

2020-07-02  Jonathan Wakely  <jwakely.gcc@gmail.com>

        Backported from master:
        2020-07-02  Jonathan Wakely  <jwakely.gcc@gmail.com>

        PR libstdc++/91153
        PR target/93224
        * testsuite/29_atomics/atomic_float/1.cc: Use different values
        for tests.
        * testsuite/29_atomics/atomic_ref/float.cc: Likewise.

2020-07-01  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-16  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/95282
        * include/bits/atomic_base.h (__atomic_impl::load): Add
        const-qualifier to parameter so that _Tp is deduced as the
        non-const type, and use _Val to get the unqualified type.
        (__atomic_impl::exchange): Use the _Val alias to remove
        volatile from the reinterpret_cast result type.
        * testsuite/29_atomics/atomic_float/95282.cc: New test.

2020-07-01  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-07-01  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94627
        * include/bits/regex.h (operator==, operator!=): Remove noexcept
        equality comparisons for match_results.
        * testsuite/28_regex/match_results/94627.cc: New test.

2020-06-29  Ville Voutilainen  <ville.voutilainen@gmail.com>

        Backported from master:
        2020-06-28  Ville Voutilainen  <ville.voutilainen@gmail.com>

        PR libstdc++/95915
        * include/std/variant (_Uninitialized):
        Adjust the condition and the comment.
        * testsuite/20_util/variant/95915.cc: New.
        * testsuite/20_util/variant/compile.cc: Add new test.

2020-06-24  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-24  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/charconv (__from_chars_binary): Ignore leading zeros.
        * testsuite/20_util/from_chars/1.cc: Check "0x1" for all bases,
        not just 10 and 16.
        * testsuite/20_util/from_chars/3.cc: New test.

2020-06-24  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-24  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_algobase.h (__find_if): Add FALLTHRU markers.
        * include/std/charconv (__detail::__to_chars): Avoid
        -Wsign-compare warning.

2020-06-24  Jonathan Wakely  <jwakely@redhat.com>

        Backported from master:
        2020-06-24  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/95851
        * include/std/charconv (__to_chars_i): Check for zero-sized
        buffer unconditionally.
        * testsuite/20_util/to_chars/95851.cc: New test.

2020-06-22  Jason Merrill  <jason@redhat.com>

        * testsuite/24_iterators/move_iterator/rel_ops_c++20.cc:
        Remove greedy_ops tests.
        * testsuite/24_iterators/reverse_iterator/rel_ops_c++20.cc:
        Remove greedy_ops tests.

2020-06-11  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/95578
        * include/bits/ranges_algo.h (__lexicographical_compare_fn):
        Also check that the iterator and sentinel have the same type before
        applying the unwrapping optimization for __normal_iterator.
        Split the check into two, one for the first iterator/sentinel
        pair and another for second iterator/sentinel pair.  Remove uses
        of __niter_base, and remove uses of std::move on a
        __normal_iterator.
        * include/bits/ranges_algobase.h (__equal_fn): Likewise.
        (__copy_or_move): Likewise.  Perform similar adjustments for
        the reverse_iterator and move_iterator optimizations.  Inline
        the checks into the if-constexprs, and use using-declarations to
        make them less visually noisy.  Remove uses of __niter_wrap.
        (__copy_or_move_backward): Likewise.
        * testsuite/25_algorithms/copy/95578.cc: New test.
        * testsuite/25_algorithms/copy_backward/95578.cc: New test.
        * testsuite/25_algorithms/equal/95578.cc: New test.
        * testsuite/25_algorithms/lexicographical_compare/95578.cc: New test.
        * testsuite/25_algorithms/move/95578.cc: New test.
        * testsuite/25_algorithms/move_backward/95578.cc: New test.

2020-05-28  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/95322
        * include/bits/stl_iterator.h (__detail::_Common_iter_proxy):
        Remove and instead define it ...
        (common_iterator::_Proxy): ... here.
        (common_iterator::operator->): Use it.
        * testsuite/24_iterators/common_iterator/2.cc: New test.
        * testsuite/std/ranges/adaptors/95322.cc: New test.

2020-05-26  Alexandre Oliva  <oliva@adacore.com>

        PR libstdc++/77691
        * include/experimental/memory_resource
        (__resource_adaptor_imp::do_allocate): Handle max_align_t on
        x86-vxworks as on x86-solaris.
        (__resource_adaptor_imp::do_deallocate): Likewise.
        * testsuite/experimental/memory_resource/new_delete_resource.cc:
        Drop xfail.
        (BAD_MAX_ALIGN_T): Define on x86-vxworks as on x86-solaris.
        (test03): Drop max-align test for char-aligned alloc.

2020-05-23  Jonathan Wakely  <jwakely@redhat.com>

        Backport from mainline
        2020-05-23  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/fs_path.h (__detail::_S_range_begin)
        (__detail::_S_range_end): Remove unintentional static specifiers.
        * include/experimental/bits/fs_path.h (__detail::_S_range_begin)
        (__detail::_S_range_end): Likewise.

2020-05-23  Jonathan Wakely  <jwakely@redhat.com>

        Backport from mainline
        2020-05-23  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/95289
        * include/debug/helper_functions.h (__get_distance): Only declare
        as a constexpr function for C++14 and up.
        * testsuite/25_algorithms/copy/debug/95289.cc: New test.

2020-05-21  Jonathan Wakely  <jwakely@redhat.com>

        Backport from mainline
        2020-05-21  Jonathan Wakely  <jwakely@redhat.com>

        * include/experimental/executor (use_future_t::use_future_t()): Fix
        incorrect noexcept-specifier.
        * include/experimental/internet (basic_resolver_results): Adjust
        whitespace.
        * include/experimental/socket (__basic_socket_impl::release): Add
        member function.
        (basic_socket(io_context&, const endpoint_type&)): Fix argument to
        target constructor.
        (basic_socket::release(), basic_socket::release(error_code&)): Add
        missing member functions.
        (basic_socket::is_open()): Add nodiscard attribute.
        (basic_socket::close(error_code&)): Pass argument to base function.
        (basic_socket_acceptor::release())
        (basic_socket_acceptor::release(error_code&)): Add missing member
        functions.
        (basic_socket_acceptor::is_open()): Add nodiscard attribute.
        (basic_socket_streambuf::error()): Add noexcept.
        (basic_socket_iostream::error()): Likewise.
        * testsuite/experimental/net/socket/basic_socket.cc: New test.

2020-05-21  Jonathan Wakely  <jwakely@redhat.com>

        Backport from mainline
        2020-05-21  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93983
        * include/bits/iterator_concepts.h (__detail::__cpp17_iterator):
        Reorder constraints to avoid recursion when constructors use
        iterator_traits (LWG 3420).
        * testsuite/24_iterators/customization_points/lwg3420.cc: New test.

2020-05-12  Jonathan Wakely  <jwakely@redhat.com>

        Backport from mainline
        2020-05-04  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94906
        * src/c++17/memory_resource.cc
        (monotonic_buffer_resource::_Chunk::release): Use size_t for shift
        operands.

        Backport from mainline
        2020-05-03  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94933
        * include/bits/stl_algobase.h (__fill_a1): Make overload for byte types
        usable in constant expressions.
        * testsuite/25_algorithms/fill_n/constexpr.cc: Test with bytes and
        non-scalars.

2020-05-07  Jonathan Wakely  <jwakely@redhat.com>

        Backport from mainline
        2020-05-01  Jonathan Wakely  <jwakely@redhat.com>
                    Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/92894
        * include/bits/iterator_concepts.h (ranges::__cust_imove::_IMove):
        Add trait to determine return type and an alias for it.
        (ranges::__cust_imove::_IMove::operator()): Use __result instead of
        deduced return type.
        * testsuite/24_iterators/customization_points/92894.cc: New test.
        * testsuite/24_iterators/indirect_callable/92894.cc: New test.

2020-05-07  Release Manager

        * GCC 10.1.0 released.

2020-05-07  Eric Botcazou  <ebotcazou@adacore.com>

        * config/abi/post/sparc64-linux-gnu/baseline_symbols.txt: Update.
        * config/abi/post/sparc64-linux-gnu/32/baseline_symbols.txt: Likewise.

2020-05-06  H.J. Lu  <hongjiu.lu@intel.com>

        * config/abi/post/x86_64-linux-gnu/x32/baseline_symbols.txt: Updated.

2020-05-06  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

        * config/abi/post/i386-solaris/baseline_symbols.txt: Regenerate.
        * config/abi/post/i386-solaris/amd64/baseline_symbols.txt:
        Likewise.
        * config/abi/post/sparc-solaris/baseline_symbols.txt: Likewise.
        * config/abi/post/sparc-solaris/sparcv9/baseline_symbols.txt:
        Likewise.

2020-05-06  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/abi.xml (abi.versioning.history): Document library
        versions for GCC 9.[123] and 10.1 releases.
        * doc/html/*: Regenerate.

2020-05-06  Jakub Jelinek  <jakub@redhat.com>

        * config/abi/post/x86_64-linux-gnu/baseline_symbols.txt: Update.
        * config/abi/post/x86_64-linux-gnu/32/baseline_symbols.txt: Update.
        * config/abi/post/i386-linux-gnu/baseline_symbols.txt: Update.
        * config/abi/post/i486-linux-gnu/baseline_symbols.txt: Update.
        * config/abi/post/aarch64-linux-gnu/baseline_symbols.txt: Update.
        * config/abi/post/s390x-linux-gnu/baseline_symbols.txt: Update.
        * config/abi/post/powerpc64-linux-gnu/baseline_symbols.txt: Update.

2020-05-04  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/faq.xml: Use working link for SGI STL FAQ.
        * doc/html/*: Regenerate.

2020-05-01  Jonathan Wakely  <jwakely@redhat.com>

        Backport from mainline
        2020-05-01  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94901
        * include/std/type_traits (__is_complete_or_unbounded): Replace
        BADNAME _T with _Tp.
        * testsuite/17_intro/badnames.cc: New test.

2020-04-30  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/89510
        * include/bits/alloc_traits.h (allocator_traits::_S_construct)
        (allocator_traits::_S_destroy)
        (allocator_traits<allocator<T>>::construct): Use traits in
        noexcept-specifiers.
        * include/bits/allocator.h (allocator<void>::construct)
        (allocator<void>::destroy): Likewise.
        * include/ext/malloc_allocator.h (malloc_allocator::construct)
        (malloc_allocator::destroy): Likewise.
        * include/ext/new_allocator.h (new_allocator::construct)
        (new_allocator::destroy): Likewise.
        * testsuite/20_util/allocator/89510.cc: New test.
        * testsuite/ext/malloc_allocator/89510.cc: New test.
        * testsuite/ext/new_allocator/89510.cc: New test.

2020-04-29  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94854
        * include/bits/basic_string.tcc: Update comment about explicit
        instantiations.

2020-04-28  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/91480
        * include/bits/allocator.h (__cpp_lib_allocator_is_always_equal):
        Remove non-standard macro.
        * include/bits/stl_iterator.h (__cpp_lib_constexpr_iterator): Define
        to indicate P1032R1 support.
        * include/bits/stl_pair.h (__cpp_lib_constexpr_utility): Likewise.
        * include/std/string_view (__cpp_lib_constexpr_string_view): Likewise.
        * include/std/tuple (__cpp_lib_constexpr_tuple): Likewise.
        * include/std/version (__cpp_lib_allocator_is_always_equal): Remove.
        (__cpp_lib_constexpr_iterator, __cpp_lib_constexpr_string_view)
        (__cpp_lib_constexpr_tuple, __cpp_lib_constexpr_utility): Define.
        * testsuite/20_util/function_objects/constexpr_searcher.cc: Check
        feature test macro.
        * testsuite/20_util/tuple/cons/constexpr_allocator_arg_t.cc: Likewise.
        * testsuite/21_strings/basic_string_view/operations/copy/char/
        constexpr.cc: Likewise.
        * testsuite/24_iterators/insert_iterator/constexpr.cc: Likewise.

        PR libstdc++/94831
        * include/bits/alloc_traits.h (_S_construct): Restore placement
        new-expression for C++11/14/17 and call std::construct_at directly
        for C++20.
        * include/bits/stl_construct.h (_Construct): Revert to non-constexpr
        function returning void.
        * testsuite/20_util/specialized_algorithms/
        uninitialized_value_construct/94831.cc: New test.
        * testsuite/23_containers/vector/cons/94831.cc: New test.

2020-04-28  Patrick Palka  <ppalka@redhat.com>

        LWG 3433 subrange::advance(n) has UB when n < 0
        * include/std/ranges (subrange::prev): Fix typo.
        (subrange::advance): Handle a negative argument as per the proposed
        resolution of LWG 3433.
        * testsuite/std/ranges/subrange/lwg3433.cc: New test.

2020-04-28  Jonathan Wakely  <jwakely@redhat.com>
            Iain Sandoe  <iain@sandoe.co.uk>

        PR c++/94759
        * include/std/coroutine: Implement handing for non-
        class coroutine return types.

2020-04-24  Jonathan Wakely  <jwakely@redhat.com>

        * include/experimental/executor (service_already_exists): Make default
        constructor public (LWG 3414).
        * testsuite/experimental/net/execution_context/make_service.cc: Check
        the service_already_exists can be default constructed.

2020-04-24  Kamlesh Kumar  <kamleshbhalui@gmail.com>
            Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/90415
        PR libstdc++/92156
        * include/std/any (any): Rename template parameters for consistency
        with the standard.
        (any::_Decay): Rename to _Decay_if_not_any.
        (any::any(T&&):: Remove is_constructible from constraints. Remove
        non-standard overload.
        (any::any(in_place_type_t<T>, Args&&...))
        (any::any(in_place_type_t<T>, initializer_list<U>, Args&&...))
        (any::emplace(Args&&...))
        (any::emplace(initializer_list<U>, Args&&...)):
        Use decay_t instead of _Decay.
        * testsuite/20_util/any/cons/90415.cc: New test.
        * testsuite/20_util/any/cons/92156.cc: New Test.
        * testsuite/20_util/any/misc/any_cast_neg.cc: Make dg-error directives
        more robust.
        * testsuite/20_util/any/modifiers/92156.cc: New test.

2020-04-23  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/manual/status_cxx2020.xml: Update C++20 status table.
        * doc/html/*: Regenerate.

        * include/bits/stl_iterator.h (__cpp_lib_array_constexpr): Revert
        value for C++17 to 201803L because P0858R0 is supported for C++17.
        * include/std/version (__cpp_lib_array_constexpr): Likewise.
        * testsuite/23_containers/array/element_access/constexpr_c++17.cc:
        Check for value corresponding to P0031R0 features being tested.
        * testsuite/23_containers/array/requirements/constexpr_iter.cc:
        Check for value corresponding to P0858R0 features being tested.

        * include/std/version (__cpp_lib_three_way_comparison): Define for
        freestanding builds.

2020-04-23  Thomas Rodgers  <rodgert@appliantology.com>

        * include/experimental/net/executor (system_context): Mark
        system_context::system_context() = delete.
        * testsuite/experimental/net/executor/1.cc: Add new
        test to check system_context is not default constructible.

2020-04-23  Iain Sandoe  <iain@sandoe.co.uk>

        * include/std/coroutine: Update the inline namespace to __n4861.
        Add the __cpp_lib_coroutine define, set to 201902L.
        * include/std/version: Add __cpp_lib_coroutine, set to 201902L.

2020-04-22  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/execution (__cpp_lib_execution): Define to indicate
        support for P0024R2 and P1001R2.
        * include/std/version (__cpp_lib_execution): Define.
        * testsuite/25_algorithms/pstl/feature_test.cc: Only test macro
        defined by <algorithm>, move other tests to new tests ...
        * testsuite/25_algorithms/pstl/feature_test-2.cc: New test.
        * testsuite/25_algorithms/pstl/feature_test-3.cc: New test.
        * testsuite/25_algorithms/pstl/feature_test-4.cc: New test.
        * testsuite/25_algorithms/pstl/feature_test-5.cc: New test.

        * include/bits/stl_iterator.h (__cpp_lib_array_constexpr): Define
        different values for C++17 and C++20, to indicate different feature
        sets. Update value for C++20 to indicate P1032R1 support.
        * include/std/version (__cpp_lib_array_constexpr): Likewise.
        * testsuite/23_containers/array/comparison_operators/constexpr.cc:
        Check feature test macro.
        * testsuite/23_containers/array/element_access/constexpr_c++17.cc:
        New test.
        * testsuite/23_containers/array/requirements/constexpr_fill.cc: Check
        feature test macro.
        * testsuite/23_containers/array/requirements/constexpr_iter.cc: Test
        in C++17 mode and check feature test macro.

        * include/std/utility (__cpp_lib_constexpr_algorithms): Do not define
        here.
        * testsuite/20_util/exchange/constexpr.cc: Do not expect macro to be
        defined by <utility>.

        * include/std/functional (__cpp_lib_concepts): Update macro value to
        indicate P1964R2 support.
        * include/std/version (__cpp_lib_concepts): Likewise.
        * testsuite/std/concepts/1.cc: Adjust expected value.
        * testsuite/std/concepts/2.cc: Likewise.

        * include/std/functional (__cpp_lib_constexpr_invoke): Rename to
        __cpp_lib_constexpr_functional.
        * include/std/version (__cpp_lib_constexpr_invoke): Likewise.
        * testsuite/20_util/function_objects/invoke/constexpr.cc: Adjust.

        * include/bits/ptr_traits.h (__cpp_lib_constexpr_memory): Define to
        indicate P1006R1 support.
        (__cpp_lib_to_address): Define to indicate P0653R2 support.
        * include/bits/range_access.h (__cpp_lib_ssize): Define to indicate
        P1227R2 support.
        * include/bits/ranges_algo.h (__cpp_lib_shift): Define to indicate
        P0769R2 support.
        * include/std/atomic (__cpp_lib_atomic_float): Define to indicate
        P0020R6 support.
        * include/std/memory (__cpp_lib_assume_aligned): Define to indicate
        P1007R3 support.
        * include/std/memory_resource (__cpp_lib_polymorphic_allocator):
        Define to indicate P0339R6 support.
        * include/std/string_view (__cpp_lib_starts_ends_with): Define to
        indicate P0457R2 support.
        * include/std/type_traits (__cpp_lib_is_nothrow_convertible): Define
        to indicate P0758R1 support.
        (__cpp_lib_remove_cvref): Define to indicate P0550R2 support.
        (__cpp_lib_type_identity): Define to indicate P0887R1 support.
        * include/std/version (__cpp_lib_atomic_float)
        (__cpp_lib_is_nothrow_convertible, __cpp_lib_remove_cvref)
        (__cpp_lib_type_identity, __cpp_lib_assume_aligned)
        (__cpp_lib_constexpr_memory, __cpp_lib_polymorphic_allocator)
        (__cpp_lib_shift, __cpp_lib_ssize, __cpp_lib_starts_ends_with)
        (__cpp_lib_to_address): Define.
        * testsuite/20_util/to_address/1_neg.cc: Adjust dg-error line number.

        * include/bits/stl_map.h (__cpp_lib_map_insertion): Remove old
        macro.
        * include/bits/unordered_map.h (__cpp_lib_unordered_map_insertion):
        Likewise.
        * include/std/version (__cpp_lib_map_insertion)
        (__cpp_lib_unordered_map_insertion): Remove.

        * include/std/condition_variable (__cpp_lib_jthread): Remove
        redundant definition.
        * include/std/stop_token (__cpp_lib_jthread): Update macro value to
        indicate P1869R1 support.
        * include/std/version (__cpp_lib_jthread): Update value.
        * testsuite/30_threads/condition_variable_any/stop_token/1.cc: Check
        for updated macro value.
        * testsuite/30_threads/condition_variable_any/stop_token/2.cc:
        Likewise.
        * testsuite/30_threads/jthread/1.cc: Likewise.
        * testsuite/30_threads/jthread/2.cc: Likewise.
        * testsuite/30_threads/stop_token/1.cc: Likewise.
        * testsuite/30_threads/stop_token/2.cc: Likewise.

        * testsuite/21_strings/basic_string/erasure.cc: Check for
        __cpp_lib_erase_if macro.
        * testsuite/23_containers/deque/erasure.cc: Add header name to #error
        messages.
        * testsuite/23_containers/forward_list/erasure.cc: Likewise.
        * testsuite/23_containers/list/erasure.cc: Likewise.
        * testsuite/23_containers/map/erasure.cc: Likewise.
        * testsuite/23_containers/set/erasure.cc: Likewise.
        * testsuite/23_containers/unordered_map/erasure.cc: Likewise.
        * testsuite/23_containers/unordered_set/erasure.cc: Likewise.
        * testsuite/23_containers/vector/erasure.cc: Likewise.

2020-04-21  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_iterator.h (__normal_iterator): Use synth-three-way
        to define operator<=>.
        * testsuite/24_iterators/normal_iterator/cmp_c++20.cc: New test.

        * doc/Makefile.am (xml_sources_manual): Add missing XML files.
        * doc/Makefile.in: Regenerate.
        * doc/xml/manual/status_cxx1998.xml: Refer to "this section" instead
        of "this page".
        * doc/xml/manual/status_cxx2011.xml: Formatting and other corrections
        to the C++11 status table.
        * doc/xml/manual/status_cxx2014.xml: Replace list of C++14 feature
        proposals with table matching contents of the C++14 standard.
        * doc/xml/manual/status_cxx2017.xml: Add table matching contents of
        the C++17 standard.
        * doc/html/*: Regenerate.

        PR c++/94149
        * include/std/type_traits (__is_nt_constructible_impl): Add partial
        specializations for bounded arrays with non-empty initializers.
        * testsuite/20_util/is_nothrow_constructible/value_c++20.cc: New test.

2020-04-20  Thomas Rodgers  <trodgers@redhat.com>

        * testsuite/lib/libstdc++.exp: Add additional_flags=
        -DTBB_SUPRESS_DEPRECATED_MESSAGES=1 to suppress warnings when
        compiling with a newer Thread Building Blocks.

2020-04-20  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/24_iterators/istreambuf_iterator/sentinel.cc: New test.

        * testsuite/20_util/is_constructible/51185.cc: Make test class a
        non-aggregate so that the test verifies the same thing in all -std
        modes.
        * testsuite/20_util/is_constructible/value-2.cc: Adjust expected
        results for some types when paren-init for aggregates is supported.

        * include/std/version (__cpp_lib_three_way_comparison): Update value.
        * libsupc++/compare (__cpp_lib_three_way_comparison): Likewise.
        (__detail::__synth3way): Add noexcept-specifier.

        * include/bits/stl_map.h (map): Define operator<=> and remove
        operator< for C++20.
        * include/bits/stl_multimap.h (multimap): Likewise.
        * include/bits/stl_multiset.h (multiset): Likewise.
        * include/bits/stl_set.h (set): Likewise.
        * include/bits/stl_tree.h (_Rb_tree): Likewise.
        (_Rb_tree_iterator, _Rb_tree_const_iterator): Remove redundant
        operator!= for C++20.
        * include/debug/map.h (__gnu_debug::map): Define operator<=> for C++20.
        * include/debug/multimap.h (__gnu_debug::multimap): Likewise.
        * include/debug/multiset.h (__gnu_debug::multiset): Likewise.
        * include/debug/set.h (__gnu_debug::set): Likewise.
        * testsuite/23_containers/map/operators/cmp_c++20.cc: New test.
        * testsuite/23_containers/multimap/operators/cmp_c++20.cc: New test.
        * testsuite/23_containers/multiset/operators/cmp_c++20.cc: New test.
        * testsuite/23_containers/set/operators/cmp_c++20.cc: New test.

2020-04-20  Matthias Kretz  <kretz@kde.org>

        * testsuite/lib/libstdc++.exp: Avoid illegal argument to verbose.

2020-04-19  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_queue.h (queue): Define operator<=> for C++20.
        * include/bits/stl_stack.h (stack): Likewise.
        * testsuite/23_containers/queue/cmp_c++20.cc: New test.
        * testsuite/23_containers/stack/cmp_c++20.cc: New test.

        * include/bits/unordered_map.h (unordered_map, unordered_multimap):
        Remove redundant operator!= for C++20.
        * include/bits/unordered_set.h (unordered_set, unordered_multiset):
        Likewise.
        * include/debug/unordered_map (unordered_map, unordered_multimap):
        Likewise.
        * include/debug/unordered_set (unordered_set, unordered_multiset):
        Likewise.

        PR other/94629
        * include/debug/formatter.h (_Error_formatter::_Parameter): Fix
        redundant assignment in constructor.

2020-04-18  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/chrono (duration, time_point): Define operator<=> and
        remove redundant operator!= for C++20.
        * testsuite/20_util/duration/comparison_operators/three_way.cc: New
        test.
        * testsuite/20_util/time_point/comparison_operators/three_way.cc: New
        test.

        * testsuite/util/native_type/native_priority_queue.hpp: Use
        allocator_traits to rebind allocator.

2020-04-17  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/forward_list.h (forward_list): Define operator<=> and
        remove redundant comparison operators for C++20.
        * include/bits/stl_bvector.h (vector<bool, Alloc>): Likewise.
        * include/bits/stl_deque.h (deque): Likewise.
        * include/bits/stl_iterator.h (__normal_iterator): Likewise.
        * include/bits/stl_list.h (list): Likewise.
        * include/bits/stl_vector.h (vector): Likewise.
        * include/debug/deque (__gnu_debug::deque): Likewise.
        * include/debug/forward_list (__gnu_debug::forward_list): Likewise.
        * include/debug/list (__gnu_debug::list): Likewise.
        * include/debug/safe_iterator.h (__gnu_debug::_Safe_iterator):
        Likewise.
        * include/debug/vector (__gnu_debug::vector): Likewise.
        * include/ext/pointer.h (__gnu_cxx::_Pointer_adapter): Define
        operator<=> for C++20.
        * testsuite/23_containers/deque/operators/cmp_c++20.cc: New test.
        * testsuite/23_containers/forward_list/cmp_c++20.cc: New test.
        * testsuite/23_containers/list/cmp_c++20.cc: New test.
        * testsuite/23_containers/vector/bool/cmp_c++20.cc: New test.
        * testsuite/23_containers/vector/cmp_c++20.cc: New test.

        * include/bits/basic_string.h (basic_string): Define operator<=> and
        remove redundant comparison operators for C++20.
        * include/bits/char_traits.h (__gnu_cxx::char_traits, char_traits):
        Add comparison_category members.
        (__detail::__char_traits_cmp_cat): New helper to get comparison
        category from char traits class.
        * include/bits/regex.h (regex_traits::_RegexMask::operator!=): Do not
        define for C++20.
        (sub_match): Define operator<=> and remove redundant comparison
        operators for C++20.
        (match_results): Remove redundant operator!= for C++20.
        * include/std/string_view (basic_string_view): Define operator<=> and
        remove redundant comparison operators for C++20.
        * testsuite/21_strings/basic_string/operators/char/cmp_c++20.cc: New
        test.
        * testsuite/21_strings/basic_string/operators/wchar_t/cmp_c++20.cc:
        New test.
        * testsuite/21_strings/basic_string_view/operations/copy/char/
        constexpr.cc: Initialize variable.
        * testsuite/21_strings/basic_string_view/operations/copy/wchar_t/
        constexpr.cc: Likewise.
        * testsuite/21_strings/basic_string_view/operators/char/2.cc: Add
        dg-do directive and remove comments showing incorrect signatures.
        * testsuite/21_strings/basic_string_view/operators/wchar_t/2.cc:
        Likewise.
        * testsuite/21_strings/basic_string_view/operators/char/cmp_c++20.cc:
        New test.
        * testsuite/21_strings/basic_string_view/operators/wchar_t/cmp_c++20.cc:
        New test.
        * testsuite/28_regex/sub_match/compare_c++20.cc: New test.

2020-04-16  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/unsynchronized_pool_resource/allocate.cc: Remove
        name of unused parameter.

2020-04-15  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/fs_dir.h (file_status): Define operator== for C++20.
        (directory_entry): Define operator<=> and remove redundant comparison
        operators for C++20.
        * include/bits/fs_fwd.h (space_info): Define operator== for C++20.
        * include/bits/fs_path.h (path): Define operator<=> and remove
        redundant comparison operators for C++20.
        * testsuite/27_io/filesystem/path/compare/compare.cc: Fix comment.
        * testsuite/27_io/filesystem/path/compare/lwg2936.cc: Likewise.
        * testsuite/27_io/filesystem/path/compare/path.cc: Likewise.
        * testsuite/27_io/filesystem/path/compare/strings.cc: Likewise.

        * include/bits/allocator.h (operator!=): Do not define for C++20.
        * include/bits/locale_classes.h (operator!=): Likewise.
        * include/bits/std_function.h (operator==(nullptr_t, const function&))
        (operator!=(const function&, nullptr_t))
        (operator!=(nullptr_t, const function&)): Likewise.
        * include/ext/bitmap_allocator.h (operator!=): Likewise.
        * include/ext/debug_allocator.h (operator!=): Likewise.
        * include/ext/extptr_allocator.h (operator!=): Likewise.
        * include/ext/malloc_allocator.h (operator!=): Likewise.
        * include/ext/mt_allocator.h (operator!=): Likewise.
        * include/ext/new_allocator.h (operator!=): Likewise.
        * include/ext/pool_allocator.h (operator!=): Likewise.
        * include/ext/throw_allocator.h (operator!=): Likewise.
        * include/std/bitset (bitset::operator!=): Likewise.
        * include/std/memory_resource (operator!=): Likewise.
        * include/std/scoped_allocator (operator!=): Likewise.

        * include/std/typeindex (operator<=>): Define for C++20.
        * testsuite/20_util/typeindex/comparison_operators_c++20.cc: New test.

2020-04-14  Jonathan Wakely  <jwakely@redhat.com>

        * libsupc++/compare (compare_three_way): Fix constraint so that
        BUILTIN-PTR-THREE-WAY does not require three_way_comparable_with.
        * testsuite/18_support/comparisons/object/builtin-ptr-three-way.cc:
        New test.

        PR libstdc++/94562
        * include/bits/shared_ptr.h (operator<=>): Define for C++20.
        * include/bits/shared_ptr_base.h (operator<=>): Likewise.
        * include/bits/unique_ptr.h (operator<=>): Add inline specifier.
        * testsuite/20_util/shared_ptr/comparison/cmp_c++20.cc: New test.
        * testsuite/20_util/shared_ptr/comparison/less.cc: Do not expect
        std::less<A*> to be used when comparing std::shared_ptr<A> objects in
        C++20.

        PR libstdc++/94565
        * libsupc++/compare (__unspec): Add noexcept-specifier to constructor.
        * testsuite/18_support/comparisons/categories/94565.cc: New test.

2020-04-13  Iain Sandoe  <iain@sandoe.co.uk>

        * include/std/coroutine: Update coroutines builtin define,
        per n4861.

2020-04-09  Jonathan Wakely  <jwakely@redhat.com>

        * libsupc++/compare (compare_three_way): Fix noexcept-specifier.
        (strong_order, weak_order, partial_order): Replace uses of <=> with
        compare_three_way function object (LWG 3324).
        * testsuite/18_support/comparisons/algorithms/partial_order.cc: Add
        equality operator so that X satisfies three_way_comparable.
        * testsuite/18_support/comparisons/algorithms/strong_order.cc:
        Likewise.
        * testsuite/18_support/comparisons/algorithms/weak_order.cc: Likewise.

        * include/bits/unique_ptr.h (operator<=>): Define for C++20.
        * testsuite/20_util/default_delete/48631_neg.cc: Adjust dg-error line.
        * testsuite/20_util/default_delete/void_neg.cc: Likewise.
        * testsuite/20_util/unique_ptr/comparison/compare.cc: New test.
        * testsuite/20_util/unique_ptr/comparison/compare_c++20.cc: New test.

2020-04-08  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/slice_array.h (operator==(const slice&, const slice&)):
        Define for C++20.
        * include/std/complex (operator==(const T&, const complex<T>&))
        (operator!=(const complex<T>&, const complex<T>&))
        (operator!=(const complex<T>&, const T&))
        (operator!=(const T&, const complex<T>&)): Do not declare for C++20.
        * testsuite/26_numerics/slice/compare.cc: New test.

        * include/std/charconv (to_chars_result, from_chars_result): Add
        defaulted equality comparisons for C++20.
        * testsuite/20_util/from_chars/compare.cc: New test.
        * testsuite/20_util/to_chars/compare.cc: New test.

2020-04-07  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94520
        * include/std/charconv (__integer_to_chars_result_type)
        (__integer_from_chars_result_type): Use __or_ instead of __or_v_ to
        allow use in C++14.
        * testsuite/20_util/from_chars/1.cc: Run test as C++14 and replace
        use of std::string_view with std::string.
        * testsuite/20_util/from_chars/2.cc: Likewise.
        * testsuite/20_util/to_chars/1.cc: Likewise.
        * testsuite/20_util/to_chars/2.cc: Likewise.

2020-04-06  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94498
        * include/bits/char_traits.h (__gnu_cxx::char_traits::move): Make it
        usable in constant expressions for C++20.
        (__gnu_cxx::char_traits::copy, __gnu_cxx::char_traits::assign): Add
        _GLIBCXX20_CONSTEXPR.
        (std::char_traits<char>, std::char_traits<wchar_t>)
        (std::char_traits<char8_t>): Make move, copy and assign usable in
        constant expressions for C++20.
        (std::char_traits<char16_t>, std::char_traits<char32_t>): Make move
        and copy usable in constant expressions for C++20.
        * include/std/string_view (basic_string_view::copy): Add
        _GLIBCXX20_CONSTEXPR.
        * testsuite/21_strings/basic_string_view/operations/copy/char/
        constexpr.cc: New test.
        * testsuite/21_strings/basic_string_view/operations/copy/wchar_t/
        constexpr.cc: New test.

2020-04-05  Gerald Pfeifer  <gerald@pfeifer.com>

        * doc/xml/manual/appendix_contributing.xml: Refer to Git
        documentation instead of Subversion.  Switch to https.
        * doc/html/manual/appendix_contributing.html: Regenerate.

2020-04-03  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93960
        * include/bits/ptr_traits.h (__to_address): Add special case for debug
        iterators, to avoid dereferenceable check.
        * testsuite/20_util/to_address/1_neg.cc: Adjust dg-error line number.
        * testsuite/20_util/to_address/debug.cc: New test.

2020-04-01  Andrea Corallo  <andrea.corallo@arm.com>

        * testsuite/experimental/net/execution_context/use_service.cc:
        Require pthread and gthreads.

2020-04-01  Gerald Pfeifer  <gerald@pfeifer.com>

        * doc/xml/manual/appendix_free.xml: Move "free books" list from
        fsf.org to gnu.org.
        * doc/html/manual/appendix_free.html: Regenerate.

2020-03-31  Ville Voutilainen  <ville.voutilainen@gmail.com>

        Library-side tests for parenthesized aggregate init

        PR c++/92878
        PR c++/92947

        * testsuite/20_util/allocator_traits/members/92878_92947.cc: New.
        * testsuite/20_util/any/assign/92878_92947.cc: Likewise.
        * testsuite/20_util/any/cons/92878_92947.cc: Likewise.
        * testsuite/20_util/is_constructible/92878_92947.cc: Likewise.
        * testsuite/20_util/optional/assignment/92878_92947.cc: Likewise.
        * testsuite/20_util/optional/cons/92878_92947.cc: Likewise.
        * testsuite/20_util/pair/cons/92878_92947.cc: Likewise.
        * testsuite/20_util/shared_ptr/creation/92878_92947.cc: Likewise.
        * testsuite/20_util/specialized_algorithms/construct_at/92878_92947.cc:
        Likewise.
        * testsuite/20_util/unique_ptr/creation/92878_92947.cc: Likewise.
        * testsuite/20_util/uses_allocator/92878_92947.cc: Likewise.
        * testsuite/20_util/variant/92878_92947.cc: Likewise.
        * testsuite/23_containers/deque/modifiers/emplace/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/forward_list/modifiers/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/list/modifiers/emplace/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/map/modifiers/emplace/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/multimap/modifiers/emplace/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/multiset/modifiers/emplace/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/priority_queue/92878_92947.cc: Likewise.
        * testsuite/23_containers/queue/92878_92947.cc: Likewise.
        * testsuite/23_containers/set/modifiers/emplace/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/stack/92878_92947.cc: Likewise.
        * testsuite/23_containers/unordered_map/modifiers/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/unordered_multimap/modifiers/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/unordered_multiset/modifiers/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/unordered_set/modifiers/92878_92947.cc:
        Likewise.
        * testsuite/23_containers/vector/modifiers/emplace/92878_92947.cc:
        Likewise.

2020-03-28  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/is_constructible/value-2.cc: Fix test to account
        for changes due to parenthesized aggregate-initialization in C++20.
        * testsuite/20_util/time_point/cons/81468.cc: Fix test to not clash
        with std::chrono::sys_time in C++20.

        * include/bits/stl_iterator.h (reverse_iterator): Use requires-clause
        to constrain C++20 versions of comparison operators. Fix backwards
        logic of relational operators.
        (move_iterator): Use requires-clause to constrain comparison operators
        in C++20. Do not declare non-standard same-type overloads for C++20.
        * testsuite/24_iterators/move_iterator/rel_ops_c++20.cc: Check result
        of comparisons and check using greedy_ops type.
        * testsuite/24_iterators/reverse_iterator/rel_ops_c++20.cc: Likewise.
        * testsuite/24_iterators/move_iterator/greedy_ops.cc: Remove redundant
        main function from compile-only test.
        * testsuite/24_iterators/reverse_iterator/greedy_ops.cc: Likewise.

2020-03-27  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/range_cmp.h (__cpp_lib_ranges): Define.
        * include/bits/stl_iterator.h: Check value of __cpp_concepts so that
        C++20 concepts are required.
        * include/bits/stl_iterator_base_types.h: Likewise.
        * include/std/concepts: Likewise.
        * include/std/version: Likewise.
        * testsuite/std/ranges/headers/ranges/synopsis.cc: Check feature test
        macro.

        * include/bits/stl_iterator.h (reverse_iterator::iterator_concept)
        (reverse_iterator::iterator_category): Define for C++20.
        (reverse_iterator): Define comparison operators correctly for C++20.
        (__normal_iterator): Add constraints to comparison operators for C++20.
        (move_iterator::operator++(int)) [__cpp_lib_concepts]: Define new
        overload for input iterators.
        (move_iterator): Add constraints to comparison operators for C++20.
        Define operator<=> for C++20.
        * testsuite/24_iterators/move_iterator/input_iterator.cc: New test.
        * testsuite/24_iterators/move_iterator/move_only.cc: New test.
        * testsuite/24_iterators/move_iterator/rel_ops_c++20.cc: New test.
        * testsuite/24_iterators/reverse_iterator/rel_ops_c++20.cc: New test.

        * include/bits/iterator_concepts.h (__detail::__decay_copy)
        (__detail::__member_begin, __detail::__adl_begin): Move here from
        <bits/range_access.h>.
        (__detail::__ranges_begin, __detail::__range_iter_t): Define.
        * bits/range_access.h (__cust_access::__decay_copy)
        (__cust_access::__member_begin, __cust_access::__adl_begin): Move to
        <bits/iterator_concepts.h>.
        (ranges::iterator_t): Use __detail::__range_iter_t.
        * include/bits/stl_iterator.h (back_insert_iterator): Simplify
        conditional compilation. Add _GLIBCXX20_CONSTEXPR to all members.
        (front_insert_iterator): Likewise.
        (insert_iterator): Implement changes from P0896R4 for C++20.
        * testsuite/24_iterators/back_insert_iterator/constexpr.cc: New test.
        * testsuite/24_iterators/front_insert_iterator/constexpr.cc: New test.
        * testsuite/24_iterators/headers/iterator/synopsis_c++17.cc: Adjust
        for inclusion in synopsis_c++20.cc which expects different signatures
        for some function templates.
        * testsuite/24_iterators/insert_iterator/constexpr.cc: New test.

        * include/std/type_traits (__is_array_convertible): Move definition
        to immediately after is_convertible.

2020-03-26  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/chrono (chrono::days, chrono::weeks, chrono::years)
        (chrono::months, chrono::sys_days, chrono::local_t)
        (chrono::local_time, chrono::local_seconds, chrono::local_days):
        Define for C++20.
        (chrono::time_point): Add missing static assert.
        * testsuite/20_util/time_point/requirements/duration_neg.cc: New test.
        * testsuite/std/time/clock/file/overview.cc: New test.
        * testsuite/std/time/clock/file/members.cc: New test.
        * testsuite/std/time/syn_c++20.cc: New test.

2020-03-25  Mike Crowe  <mac@mcrowe.com>

        * testsuite/30_threads/shared_timed_mutex/try_lock_until/1.cc: New
        test.
        * testsuite/30_threads/shared_timed_mutex/try_lock_until/2.cc: New
        test.

2020-03-25  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/fs_fwd.h (filesystem::__file_clock): Move to ...
        * include/std/chrono (filesystem::__file_clock): Here.
        (filesystem::__file_clock::from_sys, filesystem::__file_clock::to_sys):
        Define public member functions for C++20.
        (is_clock, is_clock_v): Define traits for C++20.
        * include/std/condition_variable (condition_variable::wait_until): Add
        check for valid clock.
        * include/std/future (_State_baseV2::wait_until): Likewise.
        * include/std/mutex (__timed_mutex_impl::_M_try_lock_until): Likewise.
        * include/std/shared_mutex (shared_timed_mutex::try_lock_shared_until):
        Likewise.
        * include/std/thread (this_thread::sleep_until): Likewise.
        * testsuite/30_threads/condition_variable/members/2.cc: Qualify
        slow_clock with new namespace.
        * testsuite/30_threads/condition_variable/members/clock_neg.cc: New
        test.
        * testsuite/30_threads/condition_variable_any/members/clock_neg.cc:
        New test.
        * testsuite/30_threads/future/members/clock_neg.cc: New test.
        * testsuite/30_threads/recursive_timed_mutex/try_lock_until/3.cc:
        Qualify slow_clock with new namespace.
        * testsuite/30_threads/recursive_timed_mutex/try_lock_until/
        clock_neg.cc: New test.
        * testsuite/30_threads/shared_future/members/clock_neg.cc: New
        test.
        * testsuite/30_threads/shared_lock/locking/clock_neg.cc: New test.
        * testsuite/30_threads/shared_timed_mutex/try_lock_until/clock_neg.cc:
        New test.
        * testsuite/30_threads/timed_mutex/try_lock_until/3.cc: Qualify
        slow_clock with new namespace.
        * testsuite/30_threads/timed_mutex/try_lock_until/4.cc: Likewise.
        * testsuite/30_threads/timed_mutex/try_lock_until/clock_neg.cc: New
        test.
        * testsuite/30_threads/unique_lock/locking/clock_neg.cc: New test.
        * testsuite/std/time/traits/is_clock.cc: New test.
        * testsuite/util/slow_clock.h (slow_clock): Move to __gnu_test
        namespace.

2020-03-21  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93245
        * include/experimental/bits/fs_path.h (path::generic_string<C,T,A>()):
        * testsuite/experimental/filesystem/path/generic/generic_string.cc:
        Improve test coverage.

        PR libstdc++/94242
        * include/bits/fs_path.h (path::_S_str_convert): Replace first
        parameter with basic_string_view so that strings with different
        allocators can be accepted.
        (path::generic_string<C,T,A>()): Use basic_string object that uses the
        right allocator type.
        * testsuite/27_io/filesystem/path/generic/94242.cc: New test.
        * testsuite/27_io/filesystem/path/generic/generic_string.cc: Improve
        test coverage.

2020-03-18  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94033
        * include/std/type_traits (__is_nt_default_constructible_atom): Remove.
        (__is_nt_default_constructible_impl): Remove.
        (__is_nothrow_default_constructible_impl): Remove.
        (__is_nt_constructible_impl): Add bool template parameter. Adjust
        partial specializations.
        (__is_nothrow_constructible_impl): Replace class template with alias
        template.
        (is_nothrow_default_constructible): Derive from alias template
        __is_nothrow_constructible_impl instead of
        __is_nothrow_default_constructible_impl.
        * testsuite/20_util/is_nothrow_constructible/94003.cc: New test.

        * include/std/stop_token (stop_token::_Stop_state_ref): Define
        comparison operators explicitly if the compiler won't synthesize them.

        * include/bits/stl_algobase.h (__lexicographical_compare_aux): Check
        __cpp_lib_concepts before using iter_reference_t.
        * include/bits/stream_iterator.h (istream_iterator): Check
        __cpp_lib_concepts before using default_sentinel_t.
        * include/bits/streambuf_iterator.h (istreambuf_iterator): Likewise.

        PR libstdc++/94203
        * include/experimental/executor (executor::executor(Executor)): Call
        make_shared directly instead of _M_create. Create _Tgt1 object.
        (executor::executor(allocator_arg_t, const ProtoAlloc&, Executor)):
        Call allocate_shared directly instead of _M_create. Create _Tgt2
        object.
        (executor::target_type): Add cast needed for new _Tgt interface.
        (executor::target): Define when RTTI is disabled. Use _Tgt::_M_func.
        (executor::_Tgt): Define the same interface whether RTTI is enabled or
        not.
        (executor::_Tgt::target_type, executor::_Tgt::target): Do not use
        std::type_info in the interface.
        (executor::_Tgt::_M_func): Add data member.
        (executor::_TgtImpl): Replace with _Tgt1 and _Tgt2 class templates.
        (executor::_Tgt1::_S_func): Define function to access target without
        depending on RTTI.
        (executor::_M_create): Remove.
        (operator==, operator!=): Simplify comparisons for executor.
        * include/experimental/socket (is_error_code_enum<socket_errc>):
        Define specialization before use.
        * testsuite/experimental/net/executor/1.cc: New test.

2020-03-16  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94199
        * include/experimental/executor (service_already_exists): Add default
        constructor. Declare make_service to be a friend.
        * testsuite/experimental/net/execution_context/make_service.cc: New
        test.

2020-03-12  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/tr1/8_c_compatibility/cstdlib/functions.cc: Do not pass
        a null pointer to functions with nonnull(1) attribute.

2020-03-11  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (split_view::_OuterIter::_OuterIter): Typo fix,
        'address' -> 'std::__addressof'.
        * testsuite/std/ranges/adaptors/split.cc: Test taking the split_view of
        a non-forward input_range.
        * testsuite/util/testsuite_iterators.h (output_iterator_wrapper): Make
        default constructor protected instead of deleted, like with
        input_iterator_wrapper.
        (test_range::iterator): Add comment explaining that this type is used
        only when the underlying wrapper is input_iterator_wrapper or
        output_iterator_wrapper.  Remove delegating defaulted constructor so
        that the inherited default constructor is used instead.

        LWG 3286 ranges::size is not required to be valid after a call to
        ranges::begin on an input range
        * include/std/ranges (subrange::subrange): Split single-argument
        constructor into two, one constrained by _S_store_size and another by
        !_S_store_size.
        (take_view::begin): Call size() before calling ranges::begin(_M_base).
        * testsuite/std/ranges/adaptors/lwg3286.cc: New test.
        * testsuite/std/ranges/subrange/lwg3286.cc: New test.

2020-03-10  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (split_view::_OuterIter::__at_end): Use __current
        instead of _M_current.
        (split_view::_OuterIter::operator++): Likewise.

        * include/std/ranges (transform_view::_Iterator::__iter_move): Remove.
        (transform_view::_Iterator::operator*): Add noexcept-specifier.
        (transform_view::_Iterator::iter_move): Inline __iter_move body here.
        (split_view::_OuterIter::__current): Add noexcept.
        (split_view::_InnerIter::__iter_swap): Remove.
        (split_view::_InnerIter::__iter_move): Remove.
        (split_view::_InnerIter::_M_i_current): New accessors.
        (split_view::_InnerIter::__at_end): Use _M_i_current().
        (split_view::_InnerIter::operator*): Likewise.
        (split_view::_InnerIter::operator++): Likewise.
        (iter_move(const _InnerIter&)): Likewise.
        (iter_swap(const _InnerIter&, const _InnerIter&)): Likewise.
        * testsuite/std/ranges/adaptors/split.cc: Check noexcept-specifier
        for iter_move and iter_swap on split_view's inner iterator.

        PR c++/94117
        * include/std/ranges (ranges::transform_view::_Iterator::iter_move):
        Change expression in noexcept-specifier to match function body.

        * testsuite/23_containers/unordered_set/allocator/ext_ptr.cc: Add
        comment explaining multiple dg-do directives.
        * testsuite/24_iterators/ostream_iterator/1.cc: Fix do-do directive
        so test is run as well as compiled.

2020-03-09  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94063
        * src/c++17/fs_path.cc (path::operator+=(const path&)): Add kluge to
        handle concatenations that change the type of the first component.
        (path::operator+=(basic_string_view<value_type>)): Likewise.
        * testsuite/27_io/filesystem/path/concat/94063.cc: New test.

2020-03-06  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (join_view::_Sentinel<_Const>): Befriend
        join_view::_Sentinel<!_Const>.
        * testsuite/std/ranges/adaptors/join.cc: Augment test.

        PR libstdc++/93978
        * include/bits/range_access.h (__cust_access::_Empty::operator()):
        Declare return type to be bool instead of auto.
        * testsuite/std/ranges/adaptors/93978.cc: New test.

2020-03-06  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94069
        * include/std/shared_mutex [!PTHREAD_RWLOCK_INITIALIZER]
        (__shared_mutex_pthread::__shared_mutex_pthread()): Remove incorrect
        second argument to __glibcxx_rwlock_init.
        * testsuite/30_threads/shared_timed_mutex/94069.cc: New test.

        PR libstdc++/93244
        * testsuite/27_io/filesystem/path/generic/generic_string.cc: Adjust
        test to not fail due to PR 94063.
        * testsuite/27_io/filesystem/path/generic/utf.cc: Likewise.
        * testsuite/27_io/filesystem/path/generic/wchar_t.cc: Likewise.

2020-03-06  Andreas Krebbel  <krebbel@linux.ibm.com>

        * src/c++11/system_error.cc: Omit the ENOTSUP case statement if it
        would match ENOSYS.

2020-03-05  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/27_io/filesystem/operations/all.cc: Mark unused variable.
        * testsuite/27_io/filesystem/operations/copy.cc: Fix typo.
        * testsuite/experimental/filesystem/operations/copy.cc: Likewise.
        * testsuite/27_io/filesystem/operations/file_size.cc: Use correct type
        for return value, and in comparison.
        * testsuite/experimental/filesystem/operations/file_size.cc: Likewise.

        PR libstdc++/94051
        * include/std/string_view: Include <bits/ostream_insert.h>.
        * testsuite/21_strings/basic_string_view/inserters/94051.cc: New test.

2020-03-04  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/cpp_type_traits.h (__memcpyable): Fix comment.

2020-03-04  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/94017
        * include/bits/ranges_algobase.h (__fill_n_fn::operator()): Refine
        condition for when to use memset, making sure to additionally check that
        the output pointer's value type is a non-volatile byte type.  Instead of
        requiring that the fill type is a byte type, just require that it's an
        integral type.
        * testsuite/20_util/specialized_algorithms/uninitialized_fill/94017.cc:
        New test.
        * testsuite/20_util/specialized_algorithms/uninitialized_fill_n/94017.cc:
        New test.
        * testsuite/25_algorithms/fill/94013.cc: Uncomment part of test that was
        blocked by PR 94017.
        * testsuite/25_algorithms/fill/94017.cc: New test.
        * testsuite/25_algorithms/fill_n/94017.cc: New test.

        LWG 3355 The memory algorithms should support move-only input iterators
        introduced by P1207
        * include/bits/ranges_uninitialized.h
        (__uninitialized_copy_fn::operator()): Use std::move to avoid attempting
        to copy __ifirst, which could be a move-only input iterator.  Use
        operator- instead of ranges::distance to compute distance from a sized
        sentinel.
        (__uninitialized_copy_n_fn::operator()): Likewise.
        (__uninitialized_move_fn::operator()): Likewise.
        (__uninitialized_move_n_fn::operator()): Likewise.
        (__uninitialized_destroy_fn::operator()): Use std::move to avoid
        attempting to copy __first.
        (__uninitialized_destroy_n_fn::operator()): Likewise.
        * testsuite/20_util/specialized_algorithms/destroy/constrained.cc:
        Augment test.
        * .../specialized_algorithms/uninitialized_copy/constrained.cc:
        Likewise.
        * .../specialized_algorithms/uninitialized_move/constrained.cc:
        Likewise.

        * testsuite/util/testsuite_iterators.h (test_range::get_iterator): Make
        protected instead of private.
        (test_sized_range_sized_sent): New.

        * testsuite/util/testsuite_iterators.h (input_iterator_wrapper_nocopy):
        New testsuite iterator.
        * testsuite/24_iterators/counted_iterator/lwg3389.cc: use it.
        * testsuite/24_iterators/move_iterator/lwg3390.cc: Likewise.

        * include/bits/ranges_uninitialized.h
        (uninitialized_copy_fn::operator()): Pass a reference type as the first
        argument to is_nothrow_assignable_v.
        (uninitialized_copy_fn::operator()): Likewise.
        (uninitialized_move_fn::operator()): Likewise.  Return an in_out_result
        with the input iterator stripped of its move_iterator.
        (uninitialized_move_n_fn::operator()): Likewise.
        (uninitialized_fill_fn::operator()): Pass a reference type as the first
        argument to is_nothrow_assignable_v.
        (uninitialized_fill_n_fn::operator()): Likewise.

2020-03-03  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/94013
        * include/bits/cpp_type_traits.h (__memcpyable, __memcmpable): New
        traits to control when to use memmove and memcmp optimizations.
        (__is_nonvolatile_trivially_copyable): New helper trait.
        * include/bits/ranges_algo.h (__lexicographical_compare_fn): Do not
        use memcmp optimization with volatile data.
        * include/bits/ranges_algobase.h (__equal_fn): Use __memcmpable.
        (__copy_or_move, __copy_or_move_backward): Use __memcpyable.
        * include/bits/stl_algobase.h (__copy_move_a2): Use __memcpyable.
        (__copy_move_backward_a2): Likewise.
        (__equal_aux1): Use __memcmpable.
        (__lexicographical_compare_aux): Do not use memcmp optimization with
        volatile data.
        * testsuite/25_algorithms/copy/94013.cc: New test.
        * testsuite/25_algorithms/copy_backward/94013.cc: New test.
        * testsuite/25_algorithms/equal/94013.cc: New test.
        * testsuite/25_algorithms/fill/94013.cc: New test.
        * testsuite/25_algorithms/lexicographical_compare/94013.cc: New test.
        * testsuite/25_algorithms/move/94013.cc: New test.
        * testsuite/25_algorithms/move_backward/94013.cc: New test.

        * include/bits/stl_algobase.h (lexicographical_compare_three_way):
        Avoid redundant iterator comparisons (LWG 3410).

2020-03-02  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93972
        * include/bits/stl_algobase.h (__memcmp): Allow pointer types to
        differ.
        * testsuite/25_algorithms/lexicographical_compare/uchar.cc: New test.

        * include/std/ranges (__detail::__maybe_empty_t): Rename to
        __maybe_present_t.
        (__adaptor::_RangeAdaptor, join_view, split_view): Use new name.

        * include/bits/ranges_algo.h (shift_right): Add 'typename' to
        dependent type.

2020-03-01  H.J. Lu  <hongjiu.lu@intel.com>

        * config/abi/post/x86_64-linux-gnu/x32/baseline_symbols.txt: Updated.

2020-02-29  John David Anglin  <danglin@gcc.gnu.org>

        * testsuite/17_intro/headers/c++1998/charset.cc: Skip on *-*-hpux*.
        * testsuite/17_intro/headers/c++2011/charset.cc: Likewise.
        * testsuite/17_intro/headers/c++2014/charset.cc: Likewise.
        * testsuite/17_intro/headers/c++2017/charset.cc: Likewise.
        * testsuite/17_intro/headers/c++2020/charset.cc: Likewise.

        * testsuite/30_threads/condition_variable_any/stop_token/wait_on.cc:
        Add libatomic option.
        * testsuite/30_threads/jthread/jthread.cc: Likewise.

2020-02-29  François Dumont  <fdumont@gcc.gnu.org>

        * include/bits/stl_algo.h
        (__find_if, __count_if, __is_permutation, std::is_permutation): Move...
        * include/bits/stl_algobase.h: ...here.
        * include/bits/hashtable_policy.h: Remove <bits/stl_algo.h> include.

2020-02-29  John David Anglin  <danglin@gcc.gnu.org>

        * testsuite/30_threads/stop_token/stop_callback.cc: Add libatomic
        option.
        * testsuite/30_threads/stop_token/stop_callback/deadlock-mt.cc:
        Likewise.
        * testsuite/30_threads/stop_token/stop_callback/deadlock.cc: Likewise.
        * testsuite/30_threads/stop_token/stop_callback/destroy.cc: Likewise.
        * testsuite/30_threads/stop_token/stop_callback/invoke.cc: Likewise.
        * testsuite/30_threads/stop_token/stop_source.cc: Likewise.
        * testsuite/30_threads/stop_token/stop_source/assign.cc: Likewise.
        * testsuite/30_threads/stop_token/stop_token.cc: Likewise.
        * testsuite/30_threads/stop_token/stop_token/stop_possible.cc:
        Likewise.

        PR libstdc++/92906
        * config/abi/post/hppa-linux-gnu/baseline_symbols.txt: Update.

2020-02-28  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/93972
        * include/bits/ranges_algo.h (__lexicographical_compare_fn::operator()):
        Fix condition for when to use memcmp, making it consistent with the
        corresponding condition used in std::lexicographical_compare.
        * testsuite/25_algorithms/lexicographical_compare/93972.cc: New test.

        * testsuite/26_numerics/headers/numeric/synopsis.cc: Add signatures for
        functions introduced in C++11, C++17 and C++2a.  Add 'constexpr' to
        existing signatures for C++2a.

2020-02-28  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/24_iterators/range_operations/advance_debug_neg.cc: Run
        test instead of just compiling it.

2020-02-28  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (reverse_view::_S_needs_cached_begin): Set to false
        whenever the underlying range models common_range.

        * include/std/ranges (__detail::_CachedPosition): New struct.
        (views::filter_view::_S_needs_cached_begin): New member variable.
        (views::filter_view::_M_cached_begin): New member variable.
        (views::filter_view::begin): Use _M_cached_begin to cache its
        result.
        (views::drop_view::_S_needs_cached_begin): New static member variable.
        (views::drop_view::_M_cached_begin): New member variable.
        (views::drop_view::begin): Use _M_cached_begin to cache its result
        when _S_needs_cached_begin.
        (views::drop_while_view::_M_cached_begin): New member variable.
        (views::drop_while_view::begin): Use _M_cached_begin to cache its
        result.
        (views::reverse_view::_S_needs_cached_begin): New static member
        variable.
        (views::reverse_view::_M_cached_begin): New member variable.
        (views::reverse_view::begin): Use _M_cached_begin to cache its result
        when _S_needs_cached_begin.
        * testsuite/std/ranges/adaptors/drop.cc: Augment test to check that
        drop_view::begin caches its result.
        * testsuite/std/ranges/adaptors/drop_while.cc: Augment test to check
        that drop_while_view::begin caches its result.
        * testsuite/std/ranges/adaptors/filter.cc: Augment test to check that
        filter_view::begin caches its result.
        * testsuite/std/ranges/adaptors/reverse.cc: Augment test to check that
        reverse_view::begin caches its result.

2020-02-28  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/27_io/filesystem/operations/last_write_time.cc: Fixes for
        filesystems that silently truncate timestamps.
        * testsuite/experimental/filesystem/operations/last_write_time.cc:
        Likewise.

        * testsuite/21_strings/basic_string/cons/char/1.cc: Disable
        -Wstringop-overflow warnings.

2020-02-27  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/lib/libstdc++.exp (v3_target_compile): Add
        -fdiagnostics-urls=never to options.

2020-02-27  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (transform_view::_Iterator<_Const>): Befriend
        _Iterator<!_Const>.
        (transform_view::_Sentinel<_Const>): Befriend _Sentinel<!_Const>.
        (take_view::_Sentinel<_Const>): Likewise.
        (take_while_view::_Sentinel<_Const>): Likewise.
        (split_view::_OuterIter<_Const>): Befriend _OuterIter<!_Const>.
        * testsuite/std/ranges/adaptors/split.cc: Augment test.
        * testsuite/std/ranges/adaptors/take.cc: Augment test.
        * testsuite/std/ranges/adaptors/take_while.cc: Augment test.
        * testsuite/std/ranges/adaptors/transform.cc: Augment test.

        * testsuite/25_algorithms/copy/constrained.cc: Don't assume that the
        base() of a vector<>::iterator is a pointer.
        * testsuite/25_algorithms/copy_backward/constrained.cc: Likewise.
        * testsuite/25_algorithms/move/constrained.cc: Likewise.
        * testsuite/25_algorithms/move_backward/constrained.cc: Likewise.
        * testsuite/25_algorithms/inplace_merge/constrained.cc: Use foo.data()
        instead of &foo[0].
        * testsuite/25_algorithms/partial_sort/constrained.cc: Likewise.
        * testsuite/25_algorithms/partial_sort_copy/constrained.cc: Likewise.
        * testsuite/25_algorithms/shuffle/constrained.cc: Likewise.
        * testsuite/25_algorithms/sort/constrained.cc: Likewise.
        * testsuite/25_algorithms/stable_sort/constrained.cc: Likewise.

2020-02-27  Jonathan Wakely  <jwakely@redhat.com>

        * include/debug/array (operator<=>): Define for C++20.
        * testsuite/23_containers/array/tuple_interface/get_debug_neg.cc:
        Adjust dg-error line numbers.
        * testsuite/23_containers/array/tuple_interface/
        tuple_element_debug_neg.cc: Likewise.

        * testsuite/23_containers/span/back_assert_neg.cc: Add #undef before
        defining _GLIBCXX_ASSERTIONS.
        * testsuite/23_containers/span/first_2_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/first_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/front_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/index_op_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/last_2_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/last_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/subspan_2_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/subspan_3_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/subspan_4_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/subspan_5_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/subspan_6_assert_neg.cc: Likewise.
        * testsuite/23_containers/span/subspan_assert_neg.cc: Likewise.

        * include/debug/string (__gnu_debug::basic_string::insert): Fix for
        C++98 where the member function of the base class returns void.

        * testsuite/util/testsuite_iterators.h (forward_iterator_wrapper): Add
        equality comparisons that support value-initialized iterators.

        * include/bits/boost_concept_check.h (__function_requires): Add
        _GLIBCXX14_CONSTEXPR.
        * testsuite/25_algorithms/min/concept_checks.cc: New test.

2020-02-26  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/93936
        * include/std/ranges (split_view::_InnerIter::operator==): Compare
        the operands' _M_i rather than their _M_i.current().
        * testsuite/std/ranges/adaptors/split.cc: Augment test.

        P1645R1 constexpr for <numeric> algorithms
        * include/bits/stl_numeric.h (iota, accumulate, inner_product,
        partial_sum, adjacent_difference): Make conditionally constexpr for
        C++20.
        * include/std/numeric (__cpp_lib_constexpr_numeric): Define this feature
        test macro.
        (reduce, transform_reduce, exclusive_scan, inclusive_scan,
        transform_exclusive_scan, transform_inclusive_scan): Make conditionally
        constexpr for C++20.
        * include/std/version (__cpp_lib_constexpr_numeric): Define.
        * testsuite/26_numerics/accumulate/constexpr.cc: New test.
        * testsuite/26_numerics/adjacent_difference/constexpr.cc: Likewise.
        * testsuite/26_numerics/exclusive_scan/constexpr.cc: Likewise.
        * testsuite/26_numerics/inclusive_scan/constexpr.cc: Likewise.
        * testsuite/26_numerics/inner_product/constexpr.cc: Likewise.
        * testsuite/26_numerics/iota/constexpr.cc: Likewise.
        * testsuite/26_numerics/partial_sum/constexpr.cc: Likewise.
        * testsuite/26_numerics/reduce/constexpr.cc: Likewise.
        * testsuite/26_numerics/transform_exclusive_scan/constexpr.cc: Likewise.
        * testsuite/26_numerics/transform_inclusive_scan/constexpr.cc: Likewise.
        * testsuite/26_numerics/transform_reduce/constexpr.cc: Likewise.

2020-02-26  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/ranges_algo.h (__lexicographical_compare_fn): Declare
        variables in smaller scope and avoid calling ranges::distance when we
        know they are pointers. Remove statically-unreachable use of
        __builtin_unreachable().
        * include/bits/stl_algobase.h (__lexicographical_compare::__lc):
        Define inline.

        * include/std/ranges (__detail::__maybe_empty_t): Define new helper
        alias.
        (__detail::__maybe_const_t): Likewise.
        (__adaptor::_RangeAdaptor): Use __maybe_empty_t.
        (transform_view, take_view, take_while_view, elements_view): Use
        __maybe_const_t.
        (join_view, split_view): Use both.

2020-02-25  Patrick Palka  <ppalka@redhat.com>

        LWG 3397 basic_istream_view::iterator should not provide
        iterator_category
        * include/std/ranges (basic_istream_view:_Iterator::iterator_category):
        Rename to ...
        (basic_istream_view:_Iterator::iterator_concept): ... this.
        * testsuite/std/ranges/istream_view.cc: Augment test.

        LWG 3325 Constrain return type of transformation function for
        transform_view
        * include/std/ranges (transform_view): Constrain the return type of the
        transformation function as per LWG 3325.
        * testsuite/std/ranges/adaptors/lwg3325_neg.cc: New test.

        LWG 3313 join_view::_Iterator::operator-- is incorrectly constrained
        * include/std/ranges (join_view::_Iterator::operator--): Require that
        range_reference_t<_Base> models common_range.
        * testsuite/std/ranges/adaptors/lwg3313_neg.cc: New test.

        LWG 3301 transform_view::_Iterator has incorrect iterator_category
        * include/std/ranges (transform_view::_Iterator::_S_iter_cat): Adjust
        determination of iterator_category as per LWG 3301.
        * testsuite/std/ranges/adaptors/transform.cc: Augment test.

        LWG 3292 iota_view is under-constrained
        * include/std/ranges (iota_view): Require that _Winc models semiregular
          as per LWG 3292.
        * testsuite/std/ranges/iota/lwg3292_neg.cc: New test.

2020-02-25  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/ranges_algobase.h (__copy_or_move): Do not use memmove
        during constant evaluation. Call __builtin_memmove directly instead of
        __memmove.
        (__copy_or_move_backward): Likewise.
        * include/bits/stl_algobase.h (__memmove): Remove.
        (__copy_move<M, true, random_access_iterator_tag>::__copy_m)
        (__copy_move_backward<M, true, random_access_iterator_tag>::__copy_m):
        Use __builtin_memmove directly instead of __memmove.
        (__copy_move_a2): Do not use memmove during constant evaluation.
        (__copy_move_backward_a2): Use _IsMove constant to select correct
        __copy_move_backward specialization.
        * testsuite/25_algorithms/copy_backward/constexpr.cc: Check for copies
        begin turned into moves during constant evaluation.

        * testsuite/25_algorithms/move_backward/93872.cc: Add test left out of
        previous commit.

        PR libstdc++/93872
        * include/bits/stl_algobase.h (__memmove): Cast away const before
        doing move assignment.
        * testsuite/25_algorithms/move/93872.cc: New test.
        * testsuite/25_algorithms/move_backward/93872.cc: New test.

2020-02-24  Patrick Palka  <ppalka@redhat.com>

        PR libstdc++/93884
        * include/bits/ranges_algobase.h (__copy_or_move,
        __copy_or_move_backward): Don't inspect the iter_value_t of the output
        iterator, instead inspect its iterator_traits directly.
        * include/bits/stl_iterator.h (back_insert_iterator::container):
        Conditionally initialize.
        (back_insert_iterator::difference_type): Conditionally define.
        (back_insert_iterator::back_insert_iterator): Conditionally define this
        default constructor.
        (front_insert_iterator::container): Conditionally initialize.
        (front_insert_iterator::difference_type): Conditionally define.
        (front_insert_iterator::front_insert_iterator): Conditionally define
        this default constructor.
        * 24_iterators/back_insert_iterator/pr93884.cc: New test.
        * 24_iterators/front_insert_iterator/pr93884.cc: New test.

        P0769R2 Add shift to <algorithm>
        * include/bits/ranges_algo.h (shift_left, shift_right): New.
        * testsuite/25_algorithms/shift_left/1.cc: New test.
        * testsuite/25_algorithms/shift_right/1.cc: New test.

2020-02-24  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stream_iterator.h (istream_iterator(default_sentinel_t)):
        Make noexcept-specifier conditional.
        * testsuite/24_iterators/istream_iterator/cons/sentinel.cc: Check
        noexcept-specifier.

        * include/bits/stream_iterator.h (istream_iterator(default_sentinel_t)):
        Add constructor.
        (operator==(istream_iterator, default_sentinel_t)): Add operator.
        (ostream_iterator::difference_type): Define to ptrdiff_t for C++20.
        * include/bits/streambuf_iterator.h
        (istreambuf_iterator(default_sentinel_t)): Add constructor.
        (operator==(istreambuf_iterator, default_sentinel_t)): Add operator.
        * testsuite/24_iterators/istream_iterator/cons/sentinel.cc:
        New test.
        * testsuite/24_iterators/istream_iterator/sentinel.cc: New test.
        * testsuite/24_iterators/istreambuf_iterator/cons/sentinel.cc:
        New test.
        * testsuite/24_iterators/istreambuf_iterator/sentinel.cc: New test.

        * include/std/ranges (__deep_const_range, __enable_view_impl): Remove.
        (ranges::enable_view): Simplify (LWG 3326).
        * include/bits/range_access.h (ranges::enable_view): Declare.
        * include/bits/regex.h (__enable_view_impl): Remove partial
        specialization.
        * include/bits/stl_multiset.h (__enable_view_impl): Likewise.
        * include/bits/stl_set.h (__enable_view_impl): Likewise.
        * include/bits/unordered_set.h (__enable_view_impl): Likewise.
        * include/debug/multiset.h (__enable_view_impl): Likewise.
        * include/debug/set.h (__enable_view_impl): Likewise.
        * include/debug/unordered_set (__enable_view_impl): Likewise.
        * include/experimental/string_view (ranges::enable_view): Define
        partial specialization.
        * include/std/span (ranges::enable_view): Likewise.
        * include/std/string_view (ranges::enable_view): Likewise.
        * testsuite/std/ranges/view.cc: Check satisfaction of updated concept.

2020-02-21  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/optional (operator<=>(optional<T>, optional<U>))
        (operator<=>(optional<T>, nullopt), operator<=>(optional<T>, U)):
        Define for C++20.
        * include/std/tuple (__tuple_cmp): New helper function for <=>.
        (operator<=>(tuple<T...>, tuple<U>...)): Define for C++20.
        * include/std/variant (operator<=>(variant<T...>, variant<T...>))
        (operator<=>(monostate, monostate)): Define for C++20.
        * testsuite/20_util/optional/relops/three_way.cc: New test.
        * testsuite/20_util/tuple/comparison_operators/three_way.cc: New test.
        * testsuite/20_util/variant/89851.cc: Move to ...
        * testsuite/20_util/variant/relops/89851.cc: ... here.
        * testsuite/20_util/variant/90008.cc: Move to ...
        * testsuite/20_util/variant/relops/90008.cc: ... here.
        * testsuite/20_util/variant/relops/three_way.cc: New test.

2020-02-20  Patrick Palka  <ppalka@redhat.com>

        * include/std/ranges (views::__adaptor::__maybe_refwrap): New utility
        function.
        (views::__adaptor::_RangeAdaptor::operator()): Add comments.  Use
        __maybe_refwrap to capture lvalue references by reference, and then use
        unwrap_reference_t to forward the by-reference captures as references.
        * testsuite/std/ranges/adaptors/split.cc: Augment test.
        * testsuite/std/ranges/adaptors/split_neg.cc: New test.

        * include/std/ranges (iota_view): Forward declare _Sentinel.
        (iota_view::_Iterator): Befriend _Sentinel.
        (iota_view::_Sentinel::_M_equal): New member function.
        (iota_view::_Sentinel::operator==): Use it.
        (views::_Iota::operator()): Forward __f using the correct type.
        * testsuite/std/ranges/access/ssize.cc (test06): Don't call views::iota
        with integers of different signedness, to appease iota_view's deduction
        guide.
        * testsuite/std/ranges/iota/iota_view.cc: Augment test.

2020-02-20  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/range_access.h (ranges::begin): Reject array of
        incomplete type.
        (ranges::end, ranges::size): Require arrays to be bounded.
        (ranges::data): Require lvalue or borrowed_range.
        (ranges::iterator_t): Remove constraint.
        * testsuite/std/ranges/access/begin.cc: Do not check array of
        incomplete type.
        * testsuite/std/ranges/access/begin_neg.cc: New test.
        * testsuite/std/ranges/access/end_neg.cc: Adjust expected error.
        * testsuite/std/ranges/access/size_neg.cc: Adjust expected error.
        * testsuite/std/ranges/access/ssize.cc: Do not check array of
        incomplete type.

        * include/std/system_error (error_category::operator<=>)
        (operator<=>(const error_code&, const error_code&))
        (operator<=>(const error_condition&, const error_condition&)): Define
        for C++20.
        * testsuite/19_diagnostics/error_category/operators/less.cc: New test.
        * testsuite/19_diagnostics/error_category/operators/three_way.cc: New
        test.
        * testsuite/19_diagnostics/error_code/operators/equal.cc: Remove
        incorrect comment.
        * testsuite/19_diagnostics/error_code/operators/less.cc: New test.
        * testsuite/19_diagnostics/error_code/operators/not_equal.cc: Remove
        incorrect comment.
        * testsuite/19_diagnostics/error_code/operators/three_way.cc: New test.
        * testsuite/19_diagnostics/error_condition/operators/equal.cc: Remove
        incorrect comment.
        * testsuite/19_diagnostics/error_condition/operators/less.cc: New test.
        * testsuite/19_diagnostics/error_condition/operators/not_equal.cc:
        Remove incorrect comment.
        * testsuite/19_diagnostics/error_condition/operators/three_way.cc: New
        test.

        * libsupc++/typeinfo (type_info::operator!=): Remove for C++20.

        * include/std/thread (thread::id::operator<=>): Define for C++20.
        * testsuite/30_threads/thread/id/70294.cc: Do not take addresses of
        functions in namespace std.
        * testsuite/30_threads/thread/id/operators_c++20.cc: New test.

2020-02-19  Patrick Palka  <ppalka@redhat.com>

        * testsuite/std/ranges/adaptors/split.cc (test03): Don't include the
        null terminator of the underlying string as part of the test_range.
        (main): Call test03.

2020-02-19  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_iterator.h (common_iterator): Add copyable<I>
        requirement (LWG 3385).
        * testsuite/24_iterators/headers/iterator/synopsis_c++20.cc: Adjust
        expected declaration.

        * include/std/ranges (take_while_view, drop_view, drop_while_view)
        (elements_view:_Iterator): Initialize data members (LWG 3364).

        * libsupc++/compare (three_way_comparable): Remove always-false check
        that should have been removed with weak_equality (P1959R0).
        (three_way_comparable_with): Likewise. Reorder requirements (LWG 3360).

        * include/std/concepts (__detail::__partially_ordered_with): Move here
        from <compare>.
        (totally_ordered, totally_ordered_with): Use __partially_ordered_with
        to simplify definition (LWG 3331).
        * libsupc++/compare (__detail::__partially_ordered_with): Move to
        <concepts>.

        * include/std/concepts (totally_ordered_with): Remove redundant
        requirement (LWG 3329).

        * include/std/ranges (__detail::__convertible_to_non_slicing): New
        helper concept.
        (__detail::__pair_like_convertible_to): Remove.
        (__detail::__pair_like_convertible_from): Add requirements for
        non-slicing conversions.
        (subrange): Constrain constructors with __convertible_to_non_slicing.
        Remove constructors from pair-like types. Add new deduction guide.
        * testsuite/std/ranges/subrange/lwg3282_neg.cc: New test.

        * include/bits/iterator_concepts.h (iter_move): Add declaration to
        prevent unqualified lookup finding a suitable declaration (LWG 3247).

        * include/std/memory_resource (polymorphic_allocator::allocate)
        (polymorphic_allocator::allocate_object): Change type of exception to
        bad_array_new_length (LWG 3237).
        * testsuite/20_util/polymorphic_allocator/lwg3237.cc: New test.

        * include/std/type_traits (__cpp_lib_unwrap_ref): Define (LWG 3348).
        * include/std/version (__cpp_lib_unwrap_ref): Likewise.
        * testsuite/20_util/unwrap_reference/1.cc: Check macro.
        * testsuite/20_util/unwrap_reference/3.cc: New test.

        * include/std/numeric (midpoint(T8, T*)): Do not check for complete
        type during overload resolution, use static assert instead (LWG 3200).
        * testsuite/26_numerics/midpoint/pointer.cc: Do not test with
        incomplete type.
        * testsuite/26_numerics/midpoint/pointer_neg.cc: New test.

        * include/std/span (span(T (&)[N])): Use non-deduced context to
        prevent first parameter from interfering with class template argument
        deduction (LWG 3369).
        * testsuite/23_containers/span/deduction.cc: Add missing 'const'.
        * testsuite/23_containers/span/lwg3255.cc: Check for construction from
        rvalues.

        * include/std/span (span::const_iterator, span::const_reverse_iterator)
        (span::cbegin(), span::cend(), span::crbegin(), span::crend()):
        Remove (LWG 3320).
        * testsuite/23_containers/span/everything.cc: Replace uses of cbegin
        and cend.
        * testsuite/20_util/specialized_algorithms/destroy/constrained.cc:
        Likewise.
        * testsuite/20_util/specialized_algorithms/uninitialized_copy/
        constrained.cc: Likewise.
        * testsuite/20_util/specialized_algorithms/
        uninitialized_default_construct/constrained.cc: Likewise.
        * testsuite/20_util/specialized_algorithms/uninitialized_fill/
        constrained.cc: Likewise.
        * testsuite/20_util/specialized_algorithms/uninitialized_move/
        constrained.cc: Likewise.
        * testsuite/20_util/specialized_algorithms/
        uninitialized_value_construct/constrained.cc: Likewise.

        * include/bits/range_access.h (range_size_t): Define alias template.
        * include/std/ranges (all_view): Rename to views::all_t (LWG 3335).
        * testsuite/std/ranges/adaptors/filter.cc: Adjust to new name.

        * include/std/ranges (filter_view, transform_view, take_view)
        (join_view, split_view, reverse_view): Remove commented-out converting
        constructors (LWG 3280).

        * include/std/memory (uninitialized_construct_using_allocator): Use
        std::construct_at (LWG 3321).

        * include/std/memory_resource (polymorphic_allocator::allocate_bytes)
        (polymorphic_allocator::allocate_object)
        (polymorphic_allocator::new_object): Add nodiscard attribute (LWG3304).

        LWG 3379. "safe" in several library names is misleading
        * include/bits/range_access.h (enable_safe_range): Rename to
        enable_borrowed_range.
        (__detail::__maybe_safe_range): Rename to __maybe_borrowed_range.
        (safe_range): Rename to borrowed_range.
        * include/bits/ranges_algo.h: Adjust to use new names.
        * include/bits/ranges_algobase.h: Likewise.
        * include/bits/ranges_uninitialized.h: Likewise.
        * include/std/ranges: Likewise.
        (safe_iterator_t): Rename to borrowed_iterator_t.
        (safe_subrange_t): Rename to borrowed_subrange_t.
        * include/std/span: Adjust to use new names.
        * include/std/string_view: Likewise.
        * include/experimental/string_view: Likewise.
        * testsuite/std/ranges/access/begin.cc: Likewise.
        * testsuite/std/ranges/access/cbegin.cc: Likewise.
        * testsuite/std/ranges/access/cdata.cc: Likewise.
        * testsuite/std/ranges/access/cend.cc: Likewise.
        * testsuite/std/ranges/access/crbegin.cc: Likewise.
        * testsuite/std/ranges/access/crend.cc: Likewise.
        * testsuite/std/ranges/access/data.cc: Likewise.
        * testsuite/std/ranges/access/end.cc: Likewise.
        * testsuite/std/ranges/access/rbegin.cc: Likewise.
        * testsuite/std/ranges/access/rend.cc: Likewise.
        * testsuite/std/ranges/safe_range.cc: Likewise.
        * testsuite/std/ranges/safe_range_types.cc: Likewise.
        * testsuite/util/testsuite_iterators.h: Likewise.

        * include/std/ranges (tuple_element<0, const subrange<I, S, K>>)
        (tuple_element<1, const subrange<I, S, K>>): Add partial
        specializations (LWG 3398).
        * testsuite/std/ranges/subrange/tuple_like.cc: New test.

        * include/bits/ranges_algo.h (__find_fn, __find_first_of_fn)
        (__adjacent_find_fn, __remove_if_fn, __remove_copy_if_fn)
        (__unique_fn, __unique_copy_fn): Remove redundant conversions to bool.

2020-02-18  Patrick Palka  <ppalka@redhat.com>

        P1983R0 Wording for GB301, US296, US292, US291, and US283
        * include/std/ranges (filter_view::pred): New member function.
        (join_view::_Iterator::_Iterator): Remove now-redundant comment since
        P1983R0 fixes the highlighted issue in the same way.
        (join_view::_Iterator<_Const>): Add friend
        join_view::_Iterator<!_Const>.
        (join_view::_M_inner): Remove mutable specifier, effectively reverting
        the proposed wording changes of P3278.
        (join_view::begin): Refine the condition for when to return a const
        iterator.
        (split_view::_OuterIter::_OuterIter): Adjust constraints.
        * testsuite/std/ranges/adaptors/filter.cc: Test that filter_view::pred
        exists and works.

2020-02-18  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93818
        * include/std/ranges (_RangeAdaptor): Add deduction guide.
        (filter_view::_Iterator): Add alias _Vp_iter and use in place of
        iterator_t<_Vp>.
        (filter_view::_Iterator::_S_iter_cat()): Add 'typename'.
        (transform_view::_Iterator): Add alias _Base_iter and use in place of
        iterator_t<_Base>.
        (transform_view::_Iterator::_S_iter_cat()): Add 'typename'.
        (join_view::_Iterator): Add _Outer_iter and _Inner_iter aliases.
        (join_view::_Iterator::_S_iter_cat()): Add 'typename'.
        (split_view::_InnerIter::_S_iter_cat()): Likewise.

        * testsuite/20_util/integer_comparisons/equal.cc: Fix invalid
        assumption that long is wider than int.
        * testsuite/20_util/integer_comparisons/greater_equal.cc: Likewise.
        * testsuite/20_util/integer_comparisons/less.cc: Likewise.
        * testsuite/20_util/integer_comparisons/less_equal.cc: Likewise.
        * testsuite/20_util/integer_comparisons/not_equal.cc: Likewise.

        P1976R2 Fixed-size span construction from dynamic range
        * include/std/span (__cpp_lib_span): Update value.
        (span(It, size_type), span(It, End)): Make conditionally explicit. Add
        assertion.
        (span(R&&), span(const span<OType, OExtent>&)): Likewise and relax
        constraints.
        (span::first<Count>(), span::last<Count>()): Use explicit type in
        return statement.
        (as_bytes, as_writable_bytes): Likewise.
        * include/std/version (__cpp_lib_span): Update value.
        * testsuite/23_containers/span/1.cc: Check new value.
        * testsuite/23_containers/span/2.cc: Check new value.
        * testsuite/23_containers/span/explicit.cc: New test.

        * include/std/span (span::__is_compatible_array): Simplify alias
        template by using requires-clause.
        (span::__is_compatible_ref): New alias template for constraining
        constructors.
        (span::__is_compatible_iterator, span::__is_compatible_range): Remove.
        (span(It, size_type), span(It, End)): Use __is_compatible_ref.
        (span(T(&)[N], span(array<T, N>&), span(const array<T, N>&)): Remove
        redundant parentheses.
        (span(R&&)): Add missing constraints.

        * include/std/span (span): Reorder members and rename template
        parameters to match declarations in the C++2a working paper.

        P2116R0 Remove tuple-like protocol support from fixed-extent span
        * include/std/span (get, tuple_size, tuple_element): Remove.
        * testsuite/23_containers/span/everything.cc: Remove checks for
        tuple-like API.
        * testsuite/23_containers/span/get_neg.cc: Remove.
        * testsuite/23_containers/span/tuple_element_dynamic_neg.cc: Remove.
        * testsuite/23_containers/span/tuple_element_oob_neg.cc: Remove.
        * testsuite/23_containers/span/tuple_size_neg.cc: Remove.

2020-02-17  Patrick Palka  <ppalka@redhat.com>

        P2106R0 Alternative wording for GB315 and GB316
        * include/bits/ranges_algo.h (in_fun_result): New.
        (for_each_result, for_each_n_result): Change into an alias of
        in_fun_result.
        (in_in_result): New.
        (mismatch_result): Change into an alias of in_in_result.
        (copy_if_result): Change into an alias of in_out_result.
        (swap_ranges_result): Change into an alias of in_in_result.
        (unary_transform_result): Change into an alias of in_out_result.
        (in_in_out_result): New.
        (binary_transform_result): Change into an alias of in_in_out_result.
        (replace_copy_result, replace_copy_if_result, remove_copy_if_result,
        remove_copy_result, unique_copy_result, reverse_copy_result,
        rotate_copy_result, partial_sort_copy_result): Change into an alias of
        in_out_result.
        (in_out_out_result): New.
        (partition_copy_result, merge_result): Change into an alias of
        in_out_out_result.
        (set_union_result, set_intersection_result): Change into an alias of
        in_in_out_result.
        (set_difference_result): Change into an alias of in_out_result.
        (set_symmetric_difference): Change into an alias of in_in_out_result.
        (min_max_result): New.
        (minmax_result, minmax_element_result): Change into an alias of
        min_max_result.
        (in_found_result): New.
        (next_permutation_result, prev_permutation_result): Change into an alias
        of in_found_result.
        (__next_permutation_fn::operator(), __prev_permutation_fn::operator()):
        Adjust following changes to next_permutation_result and
        prev_permutation_result.
        * include/bits/ranges_algobase.h (in_out_result): New.
        (copy_result, move_result, move_backward_result, copy_backward_result,
        copy_n_result): Change into an alias of in_out_result.
        * include/bits/ranges_uninitialized.h (uninitialized_copy_result,
        uninitialized_copy_n_result, uninitialized_move_result,
        uninitialized_move_n_result): Likewise.
        * testsuite/25_algorithms/next_permutation/constrained.cc: Adjust uses of
        structured bindings.
        * testsuite/25_algorithms/prev_permutation/constrained.cc: Likewise.

        P1243R4 Rangify new algorithms
        * include/bits/ranges_algo.h (for_each_n_result, __for_each_n_fn,
        for_each_n, __sample_fn, sample, __clamp_fn, clamp): New.
        * testsuite/25_algorithms/clamp/constrained.cc: New test.
        * testsuite/25_algorithms/for_each/constrained.cc: Augment test.
        * testsuite/25_algorithms/sample/constrained.cc: New test.

2020-02-17  Jonathan Wakely  <jwakely@redhat.com>

        P1964R2 Wording for boolean-testable
        * include/bits/ranges_algo.h (__find_fn, __find_first_of_fn)
        (__adjacent_find_fn): Cast result of predicate to bool.
        * include/std/concepts (__boolean): Remove.
        (__detail::__boolean_testable_impl, __detail::__boolean_testable): Add
        new helper concepts.
        (__detail::__weakly_eq_cmp_with, totally_ordered, totally_ordered_with)
        (predicate): Use __boolean_testable instead of boolean.
        * libsupc++/compare (__detail::__partially_ordered, _Synth3way):
        Likewise.

        P1970R2 Consistency for size() functions: Add ranges::ssize
        * include/bits/range_access.h (_SSize, ssize): Define for C++20.
        * testsuite/std/ranges/access/ssize.cc: New test.

        P1956R1 On the names of low-level bit manipulation functions
        * include/bits/hashtable_policy.h: Update comment.
        * include/std/bit (__ispow2, __ceil2, __floor2, __log2p1): Rename.
        (ispow2, ceil2, floor2, log2p1): Likewise.
        (__cpp_lib_int_pow2): Add feature test macro.
        * include/std/charconv (__to_chars_len_2): Adjust use of __log2p1.
        * include/std/memory (assume_aligned): Adjust use of ispow2.
        * include/std/version (__cpp_lib_int_pow2): Add.
        * libsupc++/new_opa.cc: Adjust use of __ispow2.
        * src/c++17/memory_resource.cc: Likewise, and for __ceil2 and __log2p1.
        * testsuite/17_intro/freestanding.cc: Adjust use of ispow2.
        * testsuite/26_numerics/bit/bit.pow.two/ceil2.cc: Rename to ...
        * testsuite/26_numerics/bit/bit.pow.two/bit_ceil.cc: ... here.
        * testsuite/26_numerics/bit/bit.pow.two/ceil2_neg.cc: Rename to ...
        * testsuite/26_numerics/bit/bit.pow.two/bit_ceil_neg.cc: ... here.
        * testsuite/26_numerics/bit/bit.pow.two/floor2.cc: Rename to ...
        * testsuite/26_numerics/bit/bit.pow.two/bit_floor.cc: ... here.
        * testsuite/26_numerics/bit/bit.pow.two/log2p1.cc: Rename to ...
        * testsuite/26_numerics/bit/bit.pow.two/bit_width.cc: ... here.
        * testsuite/26_numerics/bit/bit.pow.two/ispow2.cc: Rename to ...
        * testsuite/26_numerics/bit/bit.pow.two/has_single_bit.cc: ... here.

        * include/std/charconv: Add comment.

        PR libstdc++/92546 (partial)
        * include/bits/random.h (uniform_random_bit_generator): Move definition
        to <bits/uniform_int_dist.h>.
        * include/bits/ranges_algo.h: Include <bits/uniform_int_dist.h> instead
        of <bits/random.h>.
        * include/bits/ranges_algobase.h: Do not include <cmath>.
        * include/bits/uniform_int_dist.h (uniform_random_bit_generator):
        Move here.
        * include/std/ranges: Do not include <limits>.
        * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error lineno.

        PR libstdc++/92546 (partial)
        * include/Makefile.am: Add new header.
        * include/Makefile.in: Regenerate.
        * include/bits/int_limits.h: New header.
        * include/bits/parse_numbers.h (__select_int::_Select_int): Replace
        numeric_limits with __detail::__int_limits.
        * include/std/bit (__rotl, __rotr, __countl_zero, __countl_one)
        (__countr_zero, __countr_one, __popcount, __ceil2, __floor2, __log2p1):
        Likewise.
        * include/std/charconv (__to_chars_8, __from_chars_binary)
        (__from_chars_alpha_to_num, from_chars): Likewise.
        * include/std/memory_resource (polymorphic_allocator::allocate)
        (polymorphic_allocator::allocate_object): Likewise.
        * include/std/string_view (basic_string_view::_S_compare): Likewise.
        * include/std/utility (in_range): Likewise.
        * testsuite/20_util/integer_comparisons/in_range_neg.cc: Adjust for
        extra error about incomplete type __int_limits<bool>.
        * testsuite/26_numerics/bit/bit.count/countl_one.cc: Include <limits>.
        * testsuite/26_numerics/bit/bit.count/countl_zero.cc: Likewise.
        * testsuite/26_numerics/bit/bit.count/countr_one.cc: Likewise.
        * testsuite/26_numerics/bit/bit.count/countr_zero.cc: Likewise.
        * testsuite/26_numerics/bit/bit.count/popcount.cc: Likewise.
        * testsuite/26_numerics/bit/bit.pow.two/ceil2_neg.cc: Likewise.
        * testsuite/26_numerics/bit/bit.pow.two/ceil2.cc: Likewise.
        * testsuite/26_numerics/bit/bit.pow.two/floor2.cc: Likewise.
        * testsuite/26_numerics/bit/bit.pow.two/ispow2.cc: Likewise.
        * testsuite/26_numerics/bit/bit.pow.two/log2p1.cc: Likewise.
        * testsuite/26_numerics/bit/bit.rotate/rotl.cc: Likewise.
        * testsuite/26_numerics/bit/bit.rotate/rotr.cc: Likewise.

        * python/libstdcxx/v6/printers.py (StdCmpCatPrinter.to_string): Update
        value for partial_ordering::unordered.

        * include/bits/iterator_concepts.h (indirectly_copyable_storable): Add
        const-qualified expression variations.
        * include/std/concepts (copyable): Likewise.

        * include/std/type_traits (__is_standard_integer): New helper trait.
        * include/std/utility (cmp_equal, cmp_not_equal, cmp_less, cmp_greater)
        (cmp_less_equal, cmp_greater_equal, in_range): Define for C++20.
        * include/std/version (__cpp_lib_integer_comparison_functions): Define.
        * testsuite/20_util/integer_comparisons/1.cc: New test.
        * testsuite/20_util/integer_comparisons/2.cc: New test.
        * testsuite/20_util/integer_comparisons/equal.cc: New test.
        * testsuite/20_util/integer_comparisons/equal_neg.cc: New test.
        * testsuite/20_util/integer_comparisons/greater_equal.cc: New test.
        * testsuite/20_util/integer_comparisons/greater_equal_neg.cc: New test.
        * testsuite/20_util/integer_comparisons/greater_neg.cc: New test.
        * testsuite/20_util/integer_comparisons/in_range.cc: New test.
        * testsuite/20_util/integer_comparisons/in_range_neg.cc: New test.
        * testsuite/20_util/integer_comparisons/less.cc: New test.
        * testsuite/20_util/integer_comparisons/less_equal.cc: New test.
        * testsuite/20_util/integer_comparisons/less_equal_neg.cc: New test.
        * testsuite/20_util/integer_comparisons/less_neg.cc: New test.
        * testsuite/20_util/integer_comparisons/not_equal.cc: New test.
        * testsuite/20_util/integer_comparisons/not_equal_neg.cc: New test.

2020-02-16  Patrick Palka  <ppalka@redhat.com>

        * include/bits/ranges_algo.h (__lexicographical_compare_fn::operator()):
        Move code after an early exit constexpr if to under an else branch.
        * include/bits/ranges_algobase.h (__equal_fn::operator()): Likewise.

2020-02-15  Patrick Palka  <ppalka@redhat.com>

        * include/bits/ranges_algo.h: Adjust whitespace and formatting.
        * include/bits/ranges_algobase.h: Likewise.
        * include/bits/ranges_uninitialized.h: Likewise.

        * include/bits/ranges_algo.h: (adjacent_find, all_of, any_of,
        binary_search, copy_if, count, count_if, equal_range, find, find_end,
        find_first_of, find_if, find_if_not, for_each, generate, generate_n,
        includes, inplace_merge, is_heap, is_heap_until, is_partitioned,
        is_permutation, is_sorted, is_sorted_until, lexicographical_compare,
        lower_bound, make_heap, max, max_element, merge, min, min_element,
        minmax, minmax_element, mismatch, next_permutation, none_of,
        nth_element, partial_sort, partial_sort_copy, partition, partition_copy,
        partition_point, pop_heap, prev_permutation, push_heap, remove,
        remove_copy, remove_copy_if, remove_if, replace, replace_copy,
        replace_copy_if, replace_if, reverse, reverse_copy, rotate, rotate_copy,
        search, search_n, set_difference, set_intersection,
        set_symmetric_difference, set_union, shuffle, sort, sort_heap,
        stable_partition, stable_sort, swap_ranges, transform, unique,
        unique_copy, upper_bound): Convert into function objects.
        * include/bits/ranges_algobase.h: (equal, copy, move, copy_n, fill_n,
        fill, move_backward, copy_backward): Likewise.
        * include/bits/ranges_uninitialized.h (uninitialized_default_construct,
        uninitialized_default_construct_n, uninitialized_value_construct,
        uninitialized_value_construct_n, uninitialized_copy,
        uninitialized_copy_n, uninitialized_move, uninitialized_move_n,
        uninitialized_fill, uninitialized_fill_n, construct_at, destroy_at,
        destroy, destroy_n): Likewise.

        * include/bits/ranges_algo.h (ranges::__find_end): Fold into ...
        (ranges::find_end): ... here.
        (ranges::__lexicographical_compare): Fold into ...
        (ranges::lexicographical_compare): ... here.
        * include/bits/ranges_algobase.h (ranges::__equal): Fold into ...
        (ranges::equal): ... here.

2020-02-15  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/erase_if.h (__cpp_lib_erase_if): Define to 202002L.
        * include/std/deque: Likewise.
        * include/std/forward_list: Likewise.
        * include/std/list: Likewise.
        * include/std/string: Likewise.
        * include/std/vector: Likewise.
        * include/std/version: Likewise.
        * testsuite/23_containers/deque/erasure.cc: Test for new value.
        * testsuite/23_containers/forward_list/erasure.cc: Likewise.
        * testsuite/23_containers/list/erasure.cc: Likewise.
        * testsuite/23_containers/map/erasure.cc: Likewise.
        * testsuite/23_containers/set/erasure.cc: Likewise.
        * testsuite/23_containers/unordered_map/erasure.cc: Likewise.
        * testsuite/23_containers/unordered_set/erasure.cc: Likewise.
        * testsuite/23_containers/vector/erasure.cc: Likewise.

2020-02-15  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/random.h (uniform_random_bit_generator): Require min()
        and max() to be constant expressions and min() to be less than max().
        * testsuite/26_numerics/random/concept.cc: Check additional cases.
        * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error lineno.

2020-02-13  Patrick Palka  <ppalka@redhat.com>

        * include/Makefile.am: Add <bits/ranges_uninitialized.h>.
        * include/Makefile.in: Regenerate.
        * include/bits/ranges_uninitialized.h: New header.
        * include/std/memory: Include it.
        * testsuite/20_util/specialized_algorithms/destroy/constrained.cc: New
        test.
        * .../uninitialized_copy/constrained.cc: New test.
        * .../uninitialized_default_construct/constrained.cc: New test.
        * .../uninitialized_fill/constrained.cc: New test.
        * .../uninitialized_move/constrained.cc: New test.
        * .../uninitialized_value_construct/constrained.cc: New test.

        * include/Makefile.am: Add bits/ranges_algobase.h
        * include/Makefile.in: Regenerate.
        * bits/ranges_algo.h: Include <bits/ranges_algobase.h> and refactor
        existing #includes.
        (__detail::__is_normal_iterator, __detail::is_reverse_iterator,
        __detail::__is_move_iterator, copy_result, move_result,
        __equal, equal, copy_result, move_result, move_backward_result,
        copy_backward_result, __copy_or_move_backward, __copy_or_move, copy,
        move, copy_backward, move_backward, copy_n_result, copy_n, fill_n,
        fill): Split out into ...
        * bits/range_algobase.h: ... this new header.

2020-02-12  Patrick Palka  <ppalka@redhat.com>

        LWG 3389 and LWG 3390
        * include/bits/stl_iterator.h (move_move_iterator): Use std::move when
        constructing the move_iterator with __i.
        (counted_iterator::counted_iterator): Use std::move when initializing
        M_current with __i.
        * testsuite/24_iterators/counted_iterator/lwg3389.cc: New test.
        * testsuite/24_iterators/move_iterator/lwg3390.cc: New test.

2020-02-12  Sandra Loosemore  <sandra@codesourcery.com>

        PR libstdc++/79193
        PR libstdc++/88999

        * configure: Regenerated.

2020-02-12  François Dumont  <fdumont@gcc.gnu.org>

        * include/bits/hashtable.h
        (_Hashtable<>(_Hashtable&&, std::allocator_type&)): Add
        missing std namespace qualification to forward call.

2020-02-09  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/20_util/function_objects/range.cmp/equal_to.cc: Fix
        comment.
        * testsuite/20_util/function_objects/range.cmp/less.ccL Likewise.

        * include/std/ranges: Fix non-ASCII characters in comment.

        * include/bits/range_cmp.h (__detail::__eq_builtin_ptr_cmp): Require
        equality comparison to be valid and return bool.
        (__detail::__less_builtin_ptr_cmp): Likewise for less-than comparison.
        * testsuite/20_util/function_objects/range.cmp/equal_to.cc: Check
        type with ambiguous conversion to fundamental types.
        * testsuite/20_util/function_objects/range.cmp/less.cc: Likewise.

2020-02-07  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/iterator_concepts.h (iter_difference_t, iter_value_t):
        Use remove_cvref_t.
        (readable_traits): Rename to indirectly_readable_traits.
        (readable): Rename to indirectly_readable.
        (writable): Rename to indirectly_writable.
        (__detail::__iter_exchange_move): Do not use remove_reference_t.
        (indirectly_swappable): Adjust requires expression parameter types.
        expression.
        * include/bits/ranges_algo.h (ranges::transform, ranges::replace)
        (ranges::replace_if, ranges::generate_n, ranges::generate)
        (ranges::remove): Use new name for writable.
        * include/bits/stl_iterator.h (__detail::__common_iter_has_arrow):
        Use new name for readable.
        * include/ext/pointer.h (readable_traits<_Pointer_adapter<P>>): Use
        new name for readable_traits.
        * testsuite/24_iterators/associated_types/readable.traits.cc: Likewise.
        * testsuite/24_iterators/indirect_callable/projected.cc: Adjust for
        new definition of indirectly_readable.

        * include/bits/stl_iterator.h (__detail::__common_iter_ptr): Change
        to take parameters of common_iterator, instead of the common_iterator
        type itself. Fix argument for __common_iter_has_arrow constraint.
        (iterator_traits<common_iterator<I, S>>::pointer): Adjust.

2020-02-07  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/ranges (iota_view): Add braces to prevent -Wempty-body
        warning.
        (basic_istream_view::_Iterator::operator++()): Add missing return.

2020-02-07  Patrick Palka  <ppalka@redhat.com>

        * include/bits/ranges_algo.h: Remove extraneous &&.

        * include/std/ranges (ranges::__detail::__stream_extractable,
        ranges::basic_istream_view, ranges::istream_view): Define.
        * testsuite/std/ranges/istream_view: New test.

        Implement C++20 range adaptors
        * include/std/ranges: Include <bits/refwrap.h> and <tuple>.
        (subrange::_S_store_size): Mark as const instead of constexpr to
        avoid what seems to be a bug in GCC.
        (__detail::__box): Give it defaulted copy and move constructors.
        (ranges::views::_Single::operator()): Mark constexpr.
        (ranges::views::_Iota::operator()): Mark constexpr.
        (__detail::Empty): Define.
        (ranges::views::__closure::_RangeAdaptor,
        ranges::views::__closure::_RangeAdaptorClosure, ref_view, all_view,
        ranges::views::all, ranges::__detail::find_if,
        ranges::__detail::find_if_not, ranges::__detail::mismatch,
        ranges::detail::min, filter_view, ranges::views::filter, transform_view,
        ranges::views::transform, take_view, ranges::views::take,
        take_while_view, ranges::views::take_while, drop_view,
        ranges::views::drop, join_view, ranges::views::join,
        __detail::require_constant, __detail::tiny_range, split_view,
        ranges::views::split, ranges::views::_Counted, ranges::views::counted,
        common_view, ranges::views::common, reverse_view,
        ranges::views::reverse,
        ranges::views::__detail::__is_reversible_subrange,
        ranges::views::__detail::__is_reverse_view, reverse_view,
        ranges::views::reverse, __detail::__has_tuple_element, elements_view,
        ranges::views::elements, ranges::views::keys, ranges::views::values):
        Define.
        (views): Alias for ranges::views.
        (tuple_size<ranges::subrange<>>, tuple_element<0, ranges::subrange>,
        tuple_element<1, ranges::subrange>): New partial specializations.
        * testsuite/std/ranges/adaptors/all.cc: New test.
        * testsuite/std/ranges/adaptors/common.cc: Likewise.
        * testsuite/std/ranges/adaptors/counted.cc: Likewise.
        * testsuite/std/ranges/adaptors/drop.cc: Likewise.
        * testsuite/std/ranges/adaptors/drop_while.cc: Likewise.
        * testsuite/std/ranges/adaptors/elements.cc: Likewise.
        * testsuite/std/ranges/adaptors/filter.cc: Likewise.
        * testsuite/std/ranges/adaptors/join.cc: Likewise.
        * testsuite/std/ranges/adaptors/reverse.cc: Likewise.
        * testsuite/std/ranges/adaptors/split.cc: Likewise.
        * testsuite/std/ranges/adaptors/take.cc: Likewise.
        * testsuite/std/ranges/adaptors/take_while.cc: Likewise.
        * testsuite/std/ranges/adaptors/transform.cc: Likewise.

2020-02-07  Jonathan Wakely  <jwakely@redhat.com>

        * libsupc++/compare (__cmp_cat::type): Define typedef for underlying
        type of enumerations and comparison category types.
        (__cmp_cat::_Ord, __cmp_cat::_Ncmp): Add underlying type.
        (__cmp_cat::_Ncmp::unordered): Change value to 2.
        (partial_ordering::_M_value, weak_ordering::_M_value)
        (strong_ordering::_M_value): Change type to __cmp_cat::type.
        (partial_ordering::_M_is_ordered): Remove data member.
        (partial_ordering): Use second bit of _M_value for unordered. Adjust
        comparison operators.
        (weak_ordering::operator partial_ordering): Simplify to remove
        branches.
        (operator<=>(unspecified, weak_ordering)): Likewise.
        (strong_ordering::operator partial_ordering): Likewise.
        (strong_ordering::operator weak_ordering): Likewise.
        (operator<=>(unspecified, strong_ordering)): Likewise.
        * testsuite/18_support/comparisons/categories/partialord.cc: New test.
        * testsuite/18_support/comparisons/categories/strongord.cc: New test.
        * testsuite/18_support/comparisons/categories/weakord.cc: New test.

        * include/std/ranges (iota_view::_Iterator): Fix typo in name of
        __cpp_lib_three_way_comparison macro and use deduced return type for
        operator<=>.
        * testsuite/std/ranges/iota/iterator.cc: New test.

2020-02-07  Patrick Palka  <ppalka@redhat.com>
            Jonathan Wakely  <jwakely@redhat.com>

        Implement C++20 constrained algorithms
        * include/Makefile.am: Add new header.
        * include/Makefile.in: Regenerate.
        * include/std/algorithm: Include <bits/ranges_algo.h>.
        * include/bits/ranges_algo.h: New file.
        * testsuite/25_algorithms/adjacent_find/constrained.cc: New test.
        * testsuite/25_algorithms/all_of/constrained.cc: New test.
        * testsuite/25_algorithms/any_of/constrained.cc: New test.
        * testsuite/25_algorithms/binary_search/constrained.cc: New test.
        * testsuite/25_algorithms/copy/constrained.cc: New test.
        * testsuite/25_algorithms/copy_backward/constrained.cc: New test.
        * testsuite/25_algorithms/copy_if/constrained.cc: New test.
        * testsuite/25_algorithms/copy_n/constrained.cc: New test.
        * testsuite/25_algorithms/count/constrained.cc: New test.
        * testsuite/25_algorithms/count_if/constrained.cc: New test.
        * testsuite/25_algorithms/equal/constrained.cc: New test.
        * testsuite/25_algorithms/equal_range/constrained.cc: New test.
        * testsuite/25_algorithms/fill/constrained.cc: New test.
        * testsuite/25_algorithms/fill_n/constrained.cc: New test.
        * testsuite/25_algorithms/find/constrained.cc: New test.
        * testsuite/25_algorithms/find_end/constrained.cc: New test.
        * testsuite/25_algorithms/find_first_of/constrained.cc: New test.
        * testsuite/25_algorithms/find_if/constrained.cc: New test.
        * testsuite/25_algorithms/find_if_not/constrained.cc: New test.
        * testsuite/25_algorithms/for_each/constrained.cc: New test.
        * testsuite/25_algorithms/generate/constrained.cc: New test.
        * testsuite/25_algorithms/generate_n/constrained.cc: New test.
        * testsuite/25_algorithms/heap/constrained.cc: New test.
        * testsuite/25_algorithms/includes/constrained.cc: New test.
        * testsuite/25_algorithms/inplace_merge/constrained.cc: New test.
        * testsuite/25_algorithms/is_partitioned/constrained.cc: New test.
        * testsuite/25_algorithms/is_permutation/constrained.cc: New test.
        * testsuite/25_algorithms/is_sorted/constrained.cc: New test.
        * testsuite/25_algorithms/is_sorted_until/constrained.cc: New test.
        * testsuite/25_algorithms/lexicographical_compare/constrained.cc: New
        test.
        * testsuite/25_algorithms/lower_bound/constrained.cc: New test.
        * testsuite/25_algorithms/max/constrained.cc: New test.
        * testsuite/25_algorithms/max_element/constrained.cc: New test.
        * testsuite/25_algorithms/merge/constrained.cc: New test.
        * testsuite/25_algorithms/min/constrained.cc: New test.
        * testsuite/25_algorithms/min_element/constrained.cc: New test.
        * testsuite/25_algorithms/minmax/constrained.cc: New test.
        * testsuite/25_algorithms/minmax_element/constrained.cc: New test.
        * testsuite/25_algorithms/mismatch/constrained.cc: New test.
        * testsuite/25_algorithms/move/constrained.cc: New test.
        * testsuite/25_algorithms/move_backward/constrained.cc: New test.
        * testsuite/25_algorithms/next_permutation/constrained.cc: New test.
        * testsuite/25_algorithms/none_of/constrained.cc: New test.
        * testsuite/25_algorithms/nth_element/constrained.cc: New test.
        * testsuite/25_algorithms/partial_sort/constrained.cc: New test.
        * testsuite/25_algorithms/partial_sort_copy/constrained.cc: New test.
        * testsuite/25_algorithms/partition/constrained.cc: New test.
        * testsuite/25_algorithms/partition_copy/constrained.cc: New test.
        * testsuite/25_algorithms/partition_point/constrained.cc: New test.
        * testsuite/25_algorithms/prev_permutation/constrained.cc: New test.
        * testsuite/25_algorithms/remove/constrained.cc: New test.
        * testsuite/25_algorithms/remove_copy/constrained.cc: New test.
        * testsuite/25_algorithms/remove_copy_if/constrained.cc: New test.
        * testsuite/25_algorithms/remove_if/constrained.cc: New test.
        * testsuite/25_algorithms/replace/constrained.cc: New test.
        * testsuite/25_algorithms/replace_copy/constrained.cc: New test.
        * testsuite/25_algorithms/replace_copy_if/constrained.cc: New test.
        * testsuite/25_algorithms/replace_if/constrained.cc: New test.
        * testsuite/25_algorithms/reverse/constrained.cc: New test.
        * testsuite/25_algorithms/reverse_copy/constrained.cc: New test.
        * testsuite/25_algorithms/rotate/constrained.cc: New test.
        * testsuite/25_algorithms/rotate_copy/constrained.cc: New test.
        * testsuite/25_algorithms/search/constrained.cc: New test.
        * testsuite/25_algorithms/search_n/constrained.cc: New test.
        * testsuite/25_algorithms/set_difference/constrained.cc: New test.
        * testsuite/25_algorithms/set_intersection/constrained.cc: New test.
        * testsuite/25_algorithms/set_symmetric_difference/constrained.cc: New
        test.
        * testsuite/25_algorithms/set_union/constrained.cc: New test.
        * testsuite/25_algorithms/shuffle/constrained.cc: New test.
        * testsuite/25_algorithms/sort/constrained.cc: New test.
        * testsuite/25_algorithms/stable_partition/constrained.cc: New test.
        * testsuite/25_algorithms/stable_sort/constrained.cc: New test.
        * testsuite/25_algorithms/swap_ranges/constrained.cc: New test.
        * testsuite/25_algorithms/transform/constrained.cc: New test.
        * testsuite/25_algorithms/unique/constrained.cc: New test.
        * testsuite/25_algorithms/unique_copy/constrained.cc: New test.
        * testsuite/25_algorithms/upper_bound/constrained.cc: New test.

2020-02-06  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_iterator.h (__detail::__common_iter_ptr): Fix PR
        number in comment. Fix indentation.

        * include/bits/stl_algobase.h (__iter_swap, __iter_swap<true>): Remove
        redundant _GLIBCXX20_CONSTEXPR.

        * include/std/ranges (viewable_range): Replace decay_t with
        remove_cvref_t (LWG 3375).

2020-02-05  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/iterator_concepts.h (iter_reference_t)
        (iter_rvalue_reference_t, iter_common_reference_t, indirect_result_t):
        Remove workarounds for PR c++/67704.
        * testsuite/24_iterators/aliases.cc: New test.

2020-02-05  Patrick Palka  <ppalka@redhat.com>

        * include/bits/stl_iterator.h (move_iterator::move_iterator): Move __i
        when initializing _M_current.
        (move_iterator::base): Split into two overloads differing in
        ref-qualifiers as in P1207R4 for C++20.

2020-02-04  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/functional (_GLIBCXX_NOT_FN_CALL_OP): Un-define after
        use.

        PR libstdc++/93562
        * include/bits/unique_ptr.h (__uniq_ptr_impl::swap): Define.
        (unique_ptr::swap, unique_ptr<T[], D>::swap): Call it.
        * testsuite/20_util/unique_ptr/modifiers/93562.cc: New test.

2020-02-01  Andrew Burgess  <andrew.burgess@embecosm.com>

        * configure: Regenerate.

2020-01-31  Patrick Palka  <ppalka@redhat.com>

        * testsuite/24_iterators/range_operations/distance.cc: Do not assume
        test_range::end() returns the same type as test_range::begin().
        * testsuite/24_iterators/range_operations/next.cc: Likewise.
        * testsuite/24_iterators/range_operations/prev.cc: Likewise.
        * testsuite/util/testsuite_iterators.h (__gnu_test::test_range::end):
        Always return a sentinel<I>.

2020-01-29  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/92895
        * include/std/stop_token (stop_token::stop_possible()): Call new
        _M_stop_possible() function.
        (stop_token::stop_requested()): Do not use stop_possible().
        (stop_token::binary_semaphore): New class, as temporary stand-in for
        std::binary_semaphore.
        (stop_token::_Stop_cb::_M_callback): Add noexcept to type.
        (stop_token::_Stop_cb::_M_destroyed, stop_token::_Stop_cb::_M_done):
        New data members for symchronization with stop_callback destruction.
        (stop_token::_Stop_cb::_Stop_cb): Make non-template.
        (stop_token::_Stop_cb::_M_linked, stop_token::_Stop_cb::_S_execute):
        Remove.
        (stop_token::_Stop_cb::_M_run): New member function.
        (stop_token::_Stop_state::_M_stopped, stop_token::_Stop_state::_M_mtx):
        Remove.
        (stop_token::_Stop_state::_M_owners): New data member to track
        reference count for ownership.
        (stop_token::_Stop_state::_M_value): New data member combining a
        spinlock, the stop requested flag, and the reference count for
        associated stop_source objects.
        (stop_token::_Stop_state::_M_requester): New data member for
        synchronization with stop_callback destruction.
        (stop_token::_Stop_state::_M_stop_possible()): New member function.
        (stop_token::_Stop_state::_M_stop_requested()): Inspect relevant bit
        of _M_value.
        (stop_token::_Stop_state::_M_add_owner)
        (stop_token::_Stop_state::_M_release_ownership)
        (stop_token::_Stop_state::_M_add_ssrc)
        (stop_token::_Stop_state::_M_sub_ssrc): New member functions for
        updating reference counts.
        (stop_token::_Stop_state::_M_lock, stop_token::_Stop_state::_M_unlock)
        (stop_token::_Stop_state::_M_lock, stop_token::_Stop_state::_M_unlock)
        (stop_token::_Stop_state::_M_try_lock)
        (stop_token::_Stop_state::_M_try_lock_and_stop)
        (stop_token::_Stop_state::_M_do_try_lock): New member functions for
        managing spinlock.
        (stop_token::_Stop_state::_M_request_stop): Use atomic operations to
        read and update state. Release lock while running callbacks. Use new
        data members to synchronize with callback destruction.
        (stop_token::_Stop_state::_M_remove_callback): Likewise.
        (stop_token::_Stop_state::_M_register_callback): Use atomic operations
        to read and update state.
        (stop_token::_Stop_state_ref): Handle type to manage _Stop_state,
        replacing shared_ptr.
        (stop_source::stop_source(const stop_source&)): Update reference count.
        (stop_source::operator=(const stop_source&)): Likewise.
        (stop_source::~stop_source()): Likewise.
        (stop_source::stop_source(stop_source&&)): Define as defaulted.
        (stop_source::operator=(stop_source&&)): Establish postcondition on
        parameter.
        (stop_callback): Enforce preconditions on template parameter. Replace
        base class with data member of new _Cb_impl type.
        (stop_callback::stop_callback(const stop_token&, Cb&&))
        (stop_callback::stop_callback(stop_token&&, Cb&&)): Fix TOCTTOU race.
        (stop_callback::_Cb_impl): New type wrapping _Callback member and
        defining the _S_execute member function.
        * testsuite/30_threads/stop_token/stop_callback/deadlock-mt.cc: New
        test.
        * testsuite/30_threads/stop_token/stop_callback/deadlock.cc: New test.
        * testsuite/30_threads/stop_token/stop_callback/destroy.cc: New test.
        * testsuite/30_threads/stop_token/stop_callback/destructible_neg.cc:
        New test.
        * testsuite/30_threads/stop_token/stop_callback/invocable_neg.cc: New
        test.
        * testsuite/30_threads/stop_token/stop_callback/invoke.cc: New test.
        * testsuite/30_threads/stop_token/stop_source/assign.cc: New test.
        * testsuite/30_threads/stop_token/stop_token/stop_possible.cc: New
        test.

        * libsupc++/compare (__detail::__3way_builtin_ptr_cmp): Use
        three_way_comparable_with.
        (__detail::__3way_cmp_with): Remove workaround for fixed bug.
        (compare_three_way::operator()): Remove redundant constraint from
        requires-clause.
        (__detail::_Synth3way::operator()): Use three_way_comparable_with
        instead of workaround.
        * testsuite/18_support/comparisons/object/93479.cc: Prune extra
        output due to simplified constraints on compare_three_way::operator().

        PR libstdc++/93479
        * libsupc++/compare (__3way_builtin_ptr_cmp): Require <=> to be valid.
        * testsuite/18_support/comparisons/object/93479.cc: New test.

        * testsuite/std/ranges/access/end.cc: Do not assume test_range::end()
        returns the same type as test_range::begin(). Add comments.
        * testsuite/std/ranges/access/rbegin.cc: Likewise.
        * testsuite/std/ranges/access/rend.cc: Likewise.
        * testsuite/std/ranges/range.cc: Do not assume the sentinel for
        test_range is the same as its iterator type.
        * testsuite/util/testsuite_iterators.h (test_range::sentinel): Add
        operator- overloads to satisfy sized_sentinel_for when the iterator
        satisfies random_access_iterator.

2020-01-28  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93470
        * include/bits/refwrap.h (reference_wrapper::operator()): Restrict
        static assertion to object types.

        PR libstdc++/93325
        * acinclude.m4 (GLIBCXX_ENABLE_LIBSTDCXX_TIME): Use AC_SEARCH_LIBS for
        clock_gettime instead of explicit glibc version check.
        * configure: Regenerate.

2020-01-28  Martin Liska  <mliska@suse.cz>

        PR libstdc++/93478
        * include/std/atomic: Fix typo.
        * include/std/optional: Likewise.

2020-01-27  Andrew Burgess  <andrew.burgess@embecosm.com>

        * configure: Regenerate.

2020-01-27  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93426
        * include/std/span (span): Fix deduction guide.
        * testsuite/23_containers/span/deduction.cc: New test.

2020-01-24  Jonathan Wakely  <jwakely@redhat.com>

        * libsupc++/compare (__cmp_cat::_Eq): Remove enumeration type.
        (__cmp_cat::_Ord::equivalent): Add enumerator.
        (__cmp_cat::_Ord::_Less, __cmp_cat::_Ord::_Greater): Rename to less
        and greater.
        (partial_ordering, weak_ordering, strong_ordering): Remove
        constructors taking __cmp_cat::_Eq parameters. Use renamed
        enumerators.

2020-01-24  Maciej W. Rozycki  <macro@wdc.com>

        * acinclude.m4: Handle `--with-toolexeclibdir='.
        * Makefile.in: Regenerate.
        * aclocal.m4: Regenerate.
        * configure: Regenerate.
        * doc/Makefile.in: Regenerate.
        * include/Makefile.in: Regenerate.
        * libsupc++/Makefile.in: Regenerate.
        * po/Makefile.in: Regenerate.
        * python/Makefile.in: Regenerate.
        * src/Makefile.in: Regenerate.
        * src/c++11/Makefile.in: Regenerate.
        * src/c++17/Makefile.in: Regenerate.
        * src/c++98/Makefile.in: Regenerate.
        * src/filesystem/Makefile.in: Regenerate.
        * testsuite/Makefile.in: Regenerate.

2020-01-23  Alexandre Oliva <oliva@adacore.com>

        * crossconfig.m4 (GLIBCXX_CHECK_MATH_DECL): Reject macros.
        * configure: Rebuild.

        * testsuite/27_io/fpos/mbstate_t/1.cc: Zero-init mbstate_t.

2020-01-23  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/91947
        * include/Makefile.am (${host_builddir}/largefile-config.h): Simplify
        rule.
        * include/Makefile.in: Regenerate.

2020-01-20  Jonathan Wakely  <jwakely@redhat.com>

        * doc/xml/faq.xml: Fix grammar.
        * doc/xml/manual/appendix_contributing.xml: Improve instructions.
        * doc/xml/manual/spine.xml: Update copyright years.
        * doc/html/*: Regenerate.

2020-01-19  Eric S. Raymond <esr@thyrsus.com>

        * doc/xml/faq.xml: Update for SVN -> Git transition.
        * doc/xml/manual/appendix_contributing.xml: Likewise.
        * doc/xml/manual/status_cxx1998.xml: Likewise.
        * doc/xml/manual/status_cxx2011.xml: Likewise.
        * doc/xml/manual/status_cxx2014.xml: Likewise.
        * doc/xml/manual/status_cxx2017.xml: Likewise.
        * doc/xml/manual/status_cxx2020.xml: Likewise.
        * doc/xml/manual/status_cxxtr1.xml: Likewise.
        * doc/xml/manual/status_cxxtr24733.xml: Likewise.

2020-01-18  Iain Sandoe  <iain@sandoe.co.uk>

        * include/Makefile.am: Add coroutine to the std set.
        * include/Makefile.in: Regenerated.
        * include/std/coroutine: New file.

2020-01-17  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/92376
        * include/bits/c++config: Only do PSTL config when the header is
        present, to fix freestanding.
        * libsupc++/new_opa.cc [!_GLIBCXX_HOSTED]: Declare allocation
        functions if they were detected by configure.

2020-01-16  Kai-Uwe Eckhardt  <kuehro@gmx.de>
            Matthew Bauer  <mjbauer95@gmail.com>
            Jonathan Wakely  <jwakely@redhat.com>

        PR bootstrap/64271 (partial)
        * config/os/bsd/netbsd/ctype_base.h (ctype_base::mask): Change type
        to unsigned short.
        (ctype_base::alpha, ctype_base::digit, ctype_base::xdigit)
        (ctype_base::print, ctype_base::graph, ctype_base::alnum): Sync
        definitions with NetBSD upstream.
        (ctype_base::blank): Use _CTYPE_BL.
        * config/os/bsd/netbsd/ctype_configure_char.cc (_C_ctype_): Remove
        Declaration.
        (ctype<char>::classic_table): Use _C_ctype_tab_ instead of _C_ctype_.
        (ctype<char>::do_toupper, ctype<char>::do_tolower): Cast char
        parameters to unsigned char.
        * config/os/bsd/netbsd/ctype_inline.h (ctype<char>::is): Likewise.

2020-01-16  François Dumont  <fdumont@gcc.gnu.org>

        PR libstdc++/91263
        * include/bits/hashtable.h (_Hashtable<>): Make _Equality<> friend.
        * include/bits/hashtable_policy.h: Include <bits/stl_algo.h>.
        (_Equality_base): Remove.
        (_Equality<>::_M_equal): Review implementation. Use
        std::is_permutation.
        * testsuite/23_containers/unordered_multiset/operators/1.cc
        (Hash, Equal, test02, test03): New.
        * testsuite/23_containers/unordered_set/operators/1.cc
        (Hash, Equal, test02, test03): New.

2020-01-15  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93267
        * include/bits/iterator_concepts.h (__max_diff_type, __max_size_type):
        Move here from <bits/range_access.h> and define using __int128 when
        available.
        (__is_integer_like, __is_signed_integer_like): Move here from
        <bits/range_access.h>.
        (weakly_incrementable): Use __is_signed_integer_like.
        * include/bits/range_access.h (__max_diff_type, __max_size_type)
        (__is_integer_like, __is_signed_integer_like): Move to
        <bits/iterator_concepts.h>.
        (__make_unsigned_like_t): Move here from <ranges>.
        * include/std/ranges (__make_unsigned_like_t): Move to
        <bits/range_access.h>.
        (iota_view): Replace using-directive with using-declarations.
        * testsuite/std/ranges/iota/93267.cc: New test.
        * testsuite/std/ranges/iota_view.cc: Move to new 'iota' sub-directory.

2020-01-13  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93244
        * include/bits/fs_path.h (path::generic_string<C,A>)
        [_GLIBCXX_FILESYSTEM_IS_WINDOWS]: Convert root-dir to forward-slash.
        * testsuite/27_io/filesystem/path/generic/generic_string.cc: Check
        root-dir is converted to forward slash in generic pathname.
        * testsuite/27_io/filesystem/path/generic/utf.cc: New test.
        * testsuite/27_io/filesystem/path/generic/wchar_t.cc: New test.

        PR libstdc++/58605
        * include/bits/atomic_base.h (__cpp_lib_atomic_value_initialization):
        Define.
        (__atomic_flag_base, __atomic_base, __atomic_base<_PTp*>)
        (__atomic_float): Add default member initializer for C++20.
        * include/std/atomic (atomic): Likewise.
        (atomic::atomic()): Remove noexcept-specifier on default constructor.
        * include/std/version (__cpp_lib_atomic_value_initialization): Define.
        * testsuite/29_atomics/atomic/cons/assign_neg.cc: Adjust dg-error line
        number.
        * testsuite/29_atomics/atomic/cons/copy_neg.cc: Likewise.
        * testsuite/29_atomics/atomic/cons/value_init.cc: New test.
        * testsuite/29_atomics/atomic_flag/cons/value_init.cc: New test.
        * testsuite/29_atomics/atomic_flag/requirements/trivial.cc: Adjust
        expected result for is_trivially_default_constructible.
        * testsuite/29_atomics/atomic_float/requirements.cc: Likewise.
        * testsuite/29_atomics/atomic_float/value_init.cc: New test.
        * testsuite/29_atomics/atomic_integral/cons/assign_neg.cc: Likewise.
        * testsuite/29_atomics/atomic_integral/cons/copy_neg.cc: Likewise.
        * testsuite/29_atomics/atomic_integral/cons/value_init.cc
        * testsuite/29_atomics/atomic_integral/requirements/trivial.cc: Adjust
        expected results for is_trivially_default_constructible.
        * testsuite/util/testsuite_common_types.h (has_trivial_dtor): Add
        new test generator.

2020-01-10  Jonathan Wakely  <jwakely@redhat.com>

        * testsuite/util/testsuite_iterators.h: Improve comment.

        * testsuite/25_algorithms/equal/deque_iterators/1.cc: Don't use C++11
        initialization syntax.

        PR libstdc++/92285
        * include/bits/streambuf_iterator.h (istreambuf_iterator): Make type
        of base class independent of __cplusplus value.
        [__cplusplus < 201103L] (istreambuf_iterator::reference): Override the
        type defined in the base class
        * testsuite/24_iterators/istreambuf_iterator/92285.cc: New test.
        * testsuite/24_iterators/istreambuf_iterator/requirements/
        base_classes.cc: Adjust expected base class for C++98.

2020-01-09  Olivier Hainque  <hainque@adacore.com>

        * doc/xml/manual/appendix_contributing.xml: Document _C2
        as a reserved identifier, by VxWorks.
        * include/bits/stl_map.h: Rename _C2 template typenames as _Cmp2.
        * include/bits/stl_multimap.h: Likewise.

2020-01-09  Jonathan Wakely  <jwakely@redhat.com>

        * include/ext/extptr_allocator.h (_ExtPtr_allocator::operator==)
        (_ExtPtr_allocator::operator!=): Add missing const qualifiers.
        * include/ext/pointer.h (readable_traits<_Pointer_adapter<S>>): Add
        partial specialization to disambiguate the two constrained
        specializations.

        * include/experimental/type_traits (experimental::is_pod_v): Disable
        -Wdeprecated-declarations warnings around reference to std::is_pod.
        * include/std/type_traits (is_pod_v): Likewise.
        * testsuite/18_support/max_align_t/requirements/2.cc: Also check
        is_standard_layout and is_trivial. Do not check is_pod for C++20.
        * testsuite/20_util/is_pod/requirements/explicit_instantiation.cc:
        Add -Wno-deprecated for C++20.
        * testsuite/20_util/is_pod/requirements/typedefs.cc: Likewise.
        * testsuite/20_util/is_pod/value.cc: Likewise.
        * testsuite/experimental/type_traits/value.cc: Likewise.

2020-01-09  JeanHeyd "ThePhD" Meneide  <phdofthehouse@gmail.com>

        * include/bits/c++config (_GLIBCXX20_DEPRECATED): Add new macro.
        * include/std/type_traits (is_pod, is_pod_v): Deprecate for C++20.
        * testuite/20_util/is_pod/deprecated-2a.cc: New test.

2020-01-09  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93205
        * include/bits/random.h (operator>>): Check stream operation succeeds.
        * include/bits/random.tcc (operator<<): Remove redundant __ostream_type
        typedefs.
        (operator>>): Remove redundant __istream_type typedefs. Check stream
        operations succeed.
        (__extract_params): New function to fill a vector from a stream.
        * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error line.

        PR libstdc++/93208
        * config/abi/pre/gnu.ver: Add new exports.
        * include/std/memory_resource (memory_resource::~memory_resource()):
        Do not define inline.
        (monotonic_buffer_resource::~monotonic_buffer_resource()): Likewise.
        * src/c++17/memory_resource.cc (memory_resource::~memory_resource()):
        Define.
        (monotonic_buffer_resource::~monotonic_buffer_resource()): Define.
        * testsuite/20_util/monotonic_buffer_resource/93208.cc: New test.

2020-01-09  François Dumont  <fdumont@gcc.gnu.org>

        PR libstdc++/92124
        * include/bits/hashtable.h (_Hashtable<>::__alloc_node_gen_t): New
        template alias.
        (_Hashtable<>::__fwd_value_for): New.
        (_Hashtable<>::_M_assign_elements<>): Remove _NodeGenerator template
        parameter.
        (_Hashtable<>::_M_assign<>): Add _Ht template parameter.
        (_Hashtable<>::operator=(const _Hashtable<>&)): Adapt.
        (_Hashtable<>::_M_move_assign): Adapt. Replace std::move_if_noexcept
        with std::move.
        (_Hashtable<>::_Hashtable(const _Hashtable&)): Adapt.
        (_Hashtable<>::_Hashtable(const _Hashtable&, const allocator_type&)):
        Adapt.
        (_Hashtable<>::_Hashtable(_Hashtable&&, const allocator_type&)):
        Adapt.
        * testsuite/23_containers/unordered_set/92124.cc: New.

2020-01-08  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/93201
        * src/c++17/fs_ops.cc (do_remove_all): New function implementing more
        detailed error reporting for remove_all. Check result of recursive
        call before incrementing iterator.
        (remove_all(const path&), remove_all(const path&, error_code&)): Use
        do_remove_all.
        * src/filesystem/ops.cc (remove_all(const path&, error_code&)): Check
        result of recursive call before incrementing iterator.
        * testsuite/27_io/filesystem/operations/remove_all.cc: Check errors
        are reported correctly.
        * testsuite/experimental/filesystem/operations/remove_all.cc: Likewise.

2020-01-07  Thomas Rodgers  <trodgers@redhat.com>

        * include/std/condition_variable
        (condition_variable_any::wait_on): Rename to match current draft
        standard.
        (condition_variable_any::wait_on_until): Likewise.
        (condition_variable_any::wait_on_for): Likewise.
        * testsuite/30_threads/condition_variable_any/stop_token/wait_on.cc:
        Adjust tests to account for renamed methods.

2020-01-07  François Dumont  <fdumont@gcc.gnu.org>

        PR libstdc++/92124
        * include/bits/stl_tree.h
        (_Rb_tree<>::_M_move_assign(_Rb_tree&, false_type)): Replace
        std::move_if_noexcept by std::move.
        * testsuite/23_containers/map/92124.cc: New.
        * testsuite/23_containers/set/92124.cc: New.

2020-01-06  Jonathan Wakely  <jwakely@redhat.com>

        * include/std/stop_token (stop_token): Remove operator!= (LWG 3254).
        (stop_source): Likewise (LWG 3362).
        * testsuite/30_threads/stop_token/stop_source.cc: Test equality
        comparisons.

        * include/bits/stl_algobase.h (__is_byte_iter, __min_cmp)
        (lexicographical_compare_three_way): Do not depend on
        __cpp_lib_concepts.
        * include/std/version (__cpp_lib_three_way_comparison): Only define
        when __cpp_lib_concepts is defined.
        * libsupc++/compare (__cpp_lib_three_way_comparison): Likewise.

2020-01-03  Jonathan Wakely  <jwakely@redhat.com>

        * include/bits/stl_algobase.h (lexicographical_compare_three_way):
        Only define four-argument overload when __cpp_lib_concepts is defined.

2020-01-01  John David Anglin  <danglin@gcc.gnu.org>

        * config/abi/post/hppa-linux-gnu/baseline_symbols.txt: Update.

2020-01-01  Jakub Jelinek  <jakub@redhat.com>

        Update copyright years.
\f
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