libstdc++: Replace numeric_limit with __int_traits in mdspan.

Using __int_traits avoids the need to include <limits> from <mdspan>.
This in turn should reduce the size of the pre-compiled <mdspan>.
Similar refactoring was carried out for PR92546. Unfortunately,

  ./gcc/xgcc -std=c++23 -P -E -x c++ - -include mdspan | wc -l

shows a decrease by 1(!) line. This is due to bits/max_size_type.h which
includes <limits>.

libstdc++-v3/ChangeLog:

	* include/std/mdspan (__valid_static_extent): Replace
	numeric_limits with __int_traits.
	(extents::_S_ctor_explicit): Ditto.
	(extents::__static_quotient): Ditto.
	(layout_stride::mapping::mapping): Ditto.
	(mdspan::size): Ditto.
	* testsuite/23_containers/mdspan/extents/class_mandates_neg.cc:
	Update test with additional diagnostics.

Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>
Signed-off-by: Luc Grosheintz <luc.grosheintz@gmail.com>

diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan
index fdec81300d792094c9837c631a1b545796bae2c0..351018a59a51e2cb019ab50f7f41e74d409499f8 100644 (file)
--- a/libstdc++-v3/include/std/mdspan
+++ b/libstdc++-v3/include/std/mdspan
@@ -36,7 +36,6 @@
 #include <span>
 #include <array>
 #include <type_traits>
-#include <limits>
 #include <utility>
 
 #define __glibcxx_want_mdspan
@@ -250,7 +249,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     template<size_t _Extent, typename _IndexType>
       concept
       __valid_static_extent = _Extent == dynamic_extent
-       || _Extent <= numeric_limits<_IndexType>::max();
+       || _Extent <= __gnu_cxx::__int_traits<_IndexType>::__max;
 
     template<typename _Extents>
       constexpr const array<size_t, _Extents::rank()>&
@@ -351,8 +350,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        _S_ctor_explicit()
        {
          return (_S_is_less_dynamic(_Extents, _OExtents) || ...)
-           || (numeric_limits<index_type>::max()
-               < numeric_limits<_OIndexType>::max());
+           || (__gnu_cxx::__int_traits<index_type>::__max
+               < __gnu_cxx::__int_traits<_OIndexType>::__max);
        }
 
       template<size_t... _OExtents>
@@ -589,7 +588,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     template<typename _Extents,
              typename _IndexType = typename _Extents::index_type>
       consteval _IndexType
-      __static_quotient(_IndexType __nom = numeric_limits<_IndexType>::max())
+      __static_quotient(_IndexType __nom = __gnu_cxx::__int_traits<_IndexType>
+                                                   ::__max)
       {
        std::span<const size_t> __sta_exts = __static_extents<_Extents>();
        for (auto __factor : __sta_exts)
@@ -1038,12 +1038,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
          static_assert(__mdspan::__representable_size<_OExtents, index_type>,
            "The size of StridedMapping::extents_type must be representable as"
            " index_type");
-         if constexpr (cmp_greater(numeric_limits<_OIndexType>::max(),
-                                   numeric_limits<index_type>::max()))
-           __glibcxx_assert(!cmp_less(numeric_limits<index_type>::max(),
-                                      __other.required_span_size())
-               && "other.required_span_size() must be representable"
-                  " as index_type");
+         if constexpr (cmp_greater(__gnu_cxx::__int_traits<_OIndexType>::__max,
+                                   __gnu_cxx::__int_traits<index_type>::__max))
+           __glibcxx_assert(!cmp_less(
+               __gnu_cxx::__int_traits<index_type>::__max,
+               __other.required_span_size())
+             && "other.required_span_size() must be representable"
+                " as index_type");
          if constexpr (extents_type::rank() > 0)
            for (size_t __i = 0; __i < extents_type::rank(); ++__i)
              _M_strides[__i] = index_type(__other.stride(__i));
@@ -1360,7 +1361,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       size() const noexcept
       {
        __glibcxx_assert(cmp_less_equal(_M_mapping.required_span_size(),
-                                       numeric_limits<size_t>::max()));
+                                       __gnu_cxx::__int_traits<size_t>
+                                                ::__max));
        return size_type(__mdspan::__size(extents()));
       }
 

diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/extents/class_mandates_neg.cc b/libstdc++-v3/testsuite/23_containers/mdspan/extents/class_mandates_neg.cc
index 67d18feda96c1dd76071849d35b07b68e98d7c16..db5cad27e5211872f88098a5f6cc9e721e494015 100644 (file)
--- a/libstdc++-v3/testsuite/23_containers/mdspan/extents/class_mandates_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/mdspan/extents/class_mandates_neg.cc
@@ -12,3 +12,6 @@ std::extents<double, 1> e4;               // { dg-error "from here" }
 // { dg-prune-output "signed or unsigned integer" }
 // { dg-prune-output "invalid use of incomplete type" }
 // { dg-prune-output "non-constant condition for static assertion" }
+// { dg-prune-output "integer constants in boolean context" }
+// { dg-prune-output "__gnu_cxx::__numeric_traits_integer" }
+// { dg-prune-output "static assertion failed" }