Carl Love [Fri, 23 Feb 2018 17:22:10 +0000 (17:22 +0000)]
rs6000-builtin.def: Change VSIGNED2 and VUNSIGNED2 macro expansions from BU_VSX_2 to BU_P8V_VSX_2...
gcc/ChangeLog:
2018-02-23 Carl Love <cel@us.ibm.com>
* config/rs6000/rs6000-builtin.def: Change VSIGNED2 and VUNSIGNED2
macro expansions from BU_VSX_2 to BU_P8V_VSX_2 and BU_VSX_OVERLOAD_2 to
BU_P8V_OVERLOAD_2.
* config/rs6000/rs6000-c.c: Change VSX_BUILTIN_VEC_VSIGNED2 to
P8V_BUILTIN_VEC_VSIGNED2. Change VSX_BUILTIN_VEC_VUNSIGNED2 to
P8V_BUILTIN_VEC_VUNSIGNED2.
gcc/testsuite/ChangeLog:
2018-02-23 Carl Love <cel@us.ibm.com>
* gcc.target/powerpc/builtins-3-runnable.c: Move tests for vec_float2,
vec_signed2 and vec_unsigned2 to new Power 8 test file.
* gcc.target/powerpc/builtins-3-runnable-p8.c: New test file for
Power 8 tests.
Paul Thomas [Fri, 23 Feb 2018 12:35:30 +0000 (12:35 +0000)]
re PR fortran/83148 (ICE: crash_signal from toplev.c:325)
2018-02-23 Paul Thomas <pault@gcc.gnu.org>
PR fortran/83148
* trans-const.c : Clean up some whitespace issues.
* trans-expr.c (gfc_conv_initializer): If an iso_c_binding
derived type has a kind value of zero, set it to the default
integer kind.
2018-02-23 Paul Thomas <pault@gcc.gnu.org>
PR fortran/83148
* gfortran.dg/class_68.f90: New test.
Janne Blomqvist [Fri, 23 Feb 2018 09:07:24 +0000 (11:07 +0200)]
PR 84519 Handle optional QUIET specifier for STOP and ERROR STOP
Fortran 2018 adds a new QUIET specifier for the STOP and ERROR STOP
statements, in order to suppress the printing of signaling FP
exceptions and the stop code. This patch adds the necessary library
changes, but for now the new specifier is not parsed and the frontend
unconditionally adds a false value for the new argument.
Regtested on x86_64-pc-linux-gnu.
gcc/fortran/ChangeLog:
2018-02-23 Janne Blomqvist <jb@gcc.gnu.org>
PR fortran/84519
* trans-decl.c (gfc_build_builtin_function_decls): Add bool
argument to stop and error stop decls.
* trans-stmt.c (gfc_trans_stop): Add false value to argument
lists.
Vladimir Makarov [Thu, 22 Feb 2018 21:17:51 +0000 (21:17 +0000)]
re PR target/81572 (gcc-7 regression: unnecessary vector regmove on compare)
2018-02-22 Vladimir Makarov <vmakarov@redhat.com>
PR target/81572
* lra-int.h (LRA_UNKNOWN_ALT, LRA_NON_CLOBBERED_ALT): New macros.
* lra.c (lra_set_insn_recog_data, lra_update_insn_recog_data): Use
LRA_UNKNOWN_ALT.
* lra-constraints.c (curr_insn_transform): Set up
LRA_NON_CLOBBERED_ALT for moves processed on the fast path. Use
LRA_UNKNOWN_ALT.
(remove_inheritance_pseudos): Use LRA_UNKNOWN_ALT.
* lra-eliminations.c (spill_pseudos): Ditto.
(process_insn_for_elimination): Ditto.
* lra-lives.c (reg_early_clobber_p): Use the new macros.
* lra-spills.c (spill_pseudos): Use LRA_UNKNOWN_ALT and
LRA_NON_CLOBBERED_ALT.
H.J. Lu [Thu, 22 Feb 2018 17:09:06 +0000 (17:09 +0000)]
i386: Add __x86_indirect_thunk_nt_reg for -fcf-protection -mcet
nocf_check attribute can be used with -fcf-protection -mcet to disable
control-flow check by adding NOTRACK prefix before indirect branch.
When -mindirect-branch=thunk-extern -mindirect-branch-register is added,
indirect branch via register, "notrack call/jmp reg", is converted to
call/jmp __x86_indirect_thunk_nt_reg
When running on machines with CET enabled, __x86_indirect_thunk_nt_reg
can be updated to
notrack jmp reg
at run-time to restore NOTRACK prefix in the original indirect branch.
Since we don't support -mindirect-branch=thunk-extern, CET and MPX at
the same time, -mindirect-branch=thunk-extern is disallowed with
-fcf-protection=branch and -fcheck-pointer-bounds.
Tested on i686 and x86-64.
gcc/
PR target/84176
* config/i386/i386.c (ix86_set_indirect_branch_type): Issue an
error when -mindirect-branch=thunk-extern, -fcf-protection=branch
and -fcheck-pointer-bounds are used together.
(indirect_thunk_prefix): New enum.
(indirect_thunk_need_prefix): New function.
(indirect_thunk_name): Replace need_bnd_p with need_prefix. Use
"_nt" instead of "_bnd" for NOTRACK prefix.
(output_indirect_thunk): Replace need_bnd_p with need_prefix.
(output_indirect_thunk_function): Likewise.
(): Likewise.
(ix86_code_end): Update output_indirect_thunk_function calls.
(ix86_output_indirect_branch_via_reg): Replace
ix86_bnd_prefixed_insn_p with indirect_thunk_need_prefix.
(ix86_output_indirect_branch_via_push): Likewise.
(ix86_output_function_return): Likewise.
* doc/invoke.texi: Document -mindirect-branch=thunk-extern is
incompatible with -fcf-protection=branch and
-fcheck-pointer-bounds.
Due to there being no multilib mapping for Armv8-R, default multilib
builts for -march=armv4t with softfloat floating-point arithmetic is
being used. This patch maps it instead to the existing Armv7 multilibs.
Note that mapping for single-precision Armv8-R has been left out due to
there being no Arm implementation of that architecture variant.
2018-02-22 Thomas Preud'homme <thomas.preudhomme@arm.com>
gcc/
* config/arm/t-multilib: Map Armv8-R to Armv7 multilibs.
gcc/testsuite/
* gcc.target/arm/multilib.exp: Add tests for Armv8-R multilib mappings.
Janne Blomqvist [Thu, 22 Feb 2018 16:14:21 +0000 (18:14 +0200)]
PR 78534, 84509 Fix libgfortran API for PAUSE statement
This patch changes the libgfortran API for the PAUSE statement. By
passing a GFC_INTEGER_8 it handles -fdefault-integer-8, and for the
character version passing the length as a size_t.
Regtested on x86_64-pc-linux-gnu, committed as obvious.
gcc/fortran/ChangeLog:
2018-02-22 Janne Blomqvist <jb@gcc.gnu.org>
PR 78534
PR 84509
* trans-decl.c (gfc_build_builtin_function_decls): Pass
gfc_int8_type node to pause_numeric, size_type_node to
pause_string.
* trans-stmt.c (gfc_trans_pause): Likewise.
libgfortran/ChangeLog:
2018-02-22 Janne Blomqvist <jb@gcc.gnu.org>
PR 78534
PR 84509
* runtime/pause.c (pause_numeric): Modify to take GFC_INTEGER_8
argument.
(pause_string): Modify to take size_t character length argument.
Janne Blomqvist [Thu, 22 Feb 2018 09:44:31 +0000 (11:44 +0200)]
Character length cleanup for Coarray Fortran library
Following the change to use size_t for Fortran character lengths (PR
78534), this patch modifies the Coarray ABI in a similar way. The
single-image implementation that is included in libgfortran is
updated, but this needs corresponding work in the OpenCoarray library
as well for multi-image support. I also fixed the types for the STOP
and ERROR STOP implementation in libgfortran, as the calling of them
is somewhat intertwined with the calling of the corresponding CAF
functions. I'll send the OpenCoarray changes as a separate pull
request to the OpenCoarrays repository.
Regtested on x86_64-pc-linux-gnu.
gcc/fortran/ChangeLog:
2018-02-22 Janne Blomqvist <jb@gcc.gnu.org>
* gfortran.texi: Update Coarray API description.
* trans-decl.c (gfc_build_builtin_function_decls): Use size_t for
character lengths, int for exit codes.
(generate_coarray_sym_init): Use size_t for character length.
* trans-intrinsic.c (conv_co_collective): Likewise.
* trans-stmt.c (gfc_trans_lock_unlock): Likewise.
(gfc_trans_event_post_wait): Likewise.
(gfc_trans_sync): Likewise.
(gfc_trans_stop): Use size_t for character lengths, int for exit
codes.
libgfortran/ChangeLog:
2018-02-22 Janne Blomqvist <jb@gcc.gnu.org>
* libgfortran.h (stop_string): Use size_t for character length.
* runtime/stop.c (stop_string): Likewise.
(error_stop_string): Likewise.
(stop_numeric): Use int for exit code.
(error_stop_numeric): Likewise.
* caf/libcaf.h: Remove stdint.h include.
(_gfortran_caf_register): Use size_t for character length.
(_gfortran_caf_deregister): Likewise.
(_gfortran_caf_sync_all): Likewise.
(_gfortran_caf_sync_memory): Likewise.
(_gfortran_caf_sync_images): Likewise.
(_gfortran_caf_stop_numeric): Use int for exit code.
(_gfortran_caf_stop_str): Use size_t for character length.
(_gfortran_caf_error_stop_str): Likewise.
(_gfortran_caf_error_stop): Use int for exit code.
(_gfortran_caf_co_broadcast): Use size_t for character length.
(_gfortran_caf_co_sum): Likewise.
(_gfortran_caf_co_min): Likewise.
(_gfortran_caf_co_max): Likewise.
(_gfortran_caf_co_reduce): Likewise.
(_gfortran_caf_lock): Likewise.
(_gfortran_caf_unlock): Likewise.
(_gfortran_caf_event_post): Likewise.
(_gfortran_caf_event_wait): Likewise.
* caf/mpi.c (_gfortran_caf_register): Update implementation to
match prototype.
(_gfortran_caf_deregister): Likewise.
(_gfortran_caf_sync_all): Likewise.
(_gfortran_caf_sync_images): Likewise.
(_gfortran_caf_error_stop_str): Likewise.
(_gfortran_caf_error_stop): Likewise.
* caf/single.c (caf_internal_error): Likewise.
(_gfortran_caf_register): Likewise.
(_gfortran_caf_deregister): Likewise.
(_gfortran_caf_sync_all): Likewise.
(_gfortran_caf_sync_memory): Likewise.
(_gfortran_caf_sync_images): Likewise.
(_gfortran_caf_stop_numeric): Likewise.
(_gfortran_caf_stop_str): Likewise.
(_gfortran_caf_error_stop_str): Likewise.
(_gfortran_caf_error_stop): Likewise.
(_gfortran_caf_co_broadcast): Likewise.
(_gfortran_caf_co_sum): Likewise.
(_gfortran_caf_co_min): Likewise.
(_gfortran_caf_co_max): Likewise.
(_gfortran_caf_co_reduce): Likewise.
(_gfortran_caf_event_post): Likewise.
(_gfortran_caf_event_wait): Likewise.
(_gfortran_caf_lock): Likewise.
(_gfortran_caf_unlock): Likewise.
Jakub Jelinek [Thu, 22 Feb 2018 08:28:42 +0000 (09:28 +0100)]
re PR tree-optimization/84503 (store-merging miscompilation on powerpc64 with -O3 since r241789)
PR tree-optimization/84503
* gimple-ssa-store-merging.c (merged_store_group::merge_into): Compute
width as info->bitpos + info->bitsize - start.
(merged_store_group::merge_overlapping): Simplify width computation.
(check_no_overlap): New function.
(imm_store_chain_info::try_coalesce_bswap): Compute expected
start + width and last_order of the group, fail if check_no_overlap
fails.
(imm_store_chain_info::coalesce_immediate_stores): Don't merge info
to group if check_no_overlap fails.
* gcc.dg/pr84503-1.c: New test.
* gcc.dg/pr84503-2.c: New test.
rs6000: Delete meaningless arguments to define_{expand,split,peephole2}
This removes the (usually empty) constraint arguments to define_expand,
define_split, and define_peephole2: this argument is meaningless and
just noise.
* config/rs6000/altivec.md: Delete contraint arguments to
define_expand, define_split, and define_peephole2, and in
define_insn_and_split if always unused.
* config/rs6000/darwin.md: Ditto.
* config/rs6000/dfp.md: Ditto.
* config/rs6000/rs6000.md: Ditto.
* config/rs6000/sync.md: Ditto.
* config/rs6000/vector.md: Ditto.
* config/rs6000/vsx.md: Ditto.
This patch changes the remaining cases in our machine description files
to use brace blocks instead of double-quoted strings as the output
control string. This increases readability by making the blocks look
more like normal C code, mostly because backslash quoting is no longer
needed. It also removes such quoting where it was still there (usually
harmless but always confusing). and it writes "\n\t" as "\;" in one
place where we didn't already.
* config/rs6000/altivec.md: Write output control strings as braced
blocks instead of double-quoted strings.
* config/rs6000/darwin.md: Ditto.
* config/rs6000/rs6000.md: Ditto.
* config/rs6000/vector.md: Ditto.
* config/rs6000/vsx.md: Ditto.
Martin Liska [Wed, 21 Feb 2018 14:05:45 +0000 (15:05 +0100)]
Add "native" as a valid option value for -march= on aarch64 (PR driver/83193).
2018-02-21 Martin Liska <mliska@suse.cz>
PR driver/83193
* config/aarch64/aarch64.c (aarch64_print_hint_for_core_or_arch):
Add "native" as a possible value.
* config/aarch64/aarch64.h (HAVE_LOCAL_CPU_DETECT): Define
the macro when native cpu detection is available.
Martin Liska [Wed, 21 Feb 2018 14:05:17 +0000 (15:05 +0100)]
Add "native" as a valid option value for -march= on arm (PR driver/83193).
2018-02-21 Martin Liska <mliska@suse.cz>
PR driver/83193
* common/config/arm/arm-common.c (arm_print_hint_for_arch_option):
Add "native" as a possible value.
* config/arm/arm.h (HAVE_LOCAL_CPU_DETECT): Define the macro
when native cpu detection is available.
Jakub Jelinek [Wed, 21 Feb 2018 10:35:46 +0000 (11:35 +0100)]
re PR tree-optimization/84478 (pdftex miscompilation on i386)
PR tree-optimization/84478
* gimple-fold.h (get_range_strlen): Add a bool argument defaulted to
false.
* gimple-fold.c (get_range_strlen): Make minlen const and assume it
can't be NULL. Change FUZZY from bool to int, for 1 add PHI/COND_EXPR
support which is conservatively correct, for 2 only stay conservative
for maxlen. Formatting and comment capitalization fixes. Add STRICT
argument to the 2 argument get_range_strlen, adjust 6 arg
get_range_strlen caller and clear minmaxlen[0] and [1] if it returned
false.
(get_maxval_strlen): Adjust 6 arg get_range_strlen caller.
(gimple_fold_builtin_strlen): Pass true as last argument to
get_range_strlen.
* gcc.c-torture/execute/pr84478.c: New test.
Co-Authored-By: Martin Sebor <msebor@redhat.com>
From-SVN: r257870
Martin Sebor [Tue, 20 Feb 2018 20:22:01 +0000 (20:22 +0000)]
PR middle-end/84095 - false-positive -Wrestrict warnings for memcpy within array
gcc/ChangeLog:
PR middle-end/84095
* gimple-ssa-warn-restrict.c (builtin_memref::extend_offset_range): New.
(builtin_memref::set_base_and_offset): Same. Handle inner references.
(builtin_memref::builtin_memref): Factor out parts into
set_base_and_offset and call it.
gcc/testsuite/ChangeLog:
PR middle-end/84095
* c-c++-common/Warray-bounds-3.c: Adjust text of expected warnings.
* c-c++-common/Wrestrict.c: Same.
* gcc.dg/Wrestrict-6.c: Same.
* gcc.dg/Warray-bounds-27.c: New test.
* gcc.dg/Wrestrict-8.c: New test.
* gcc.dg/Wrestrict-9.c: New test.
* gcc.dg/pr84095.c: New test.
re PR target/84406 ([MSP430] ICE on valid code in find_widening_optab_handler_and_mode, at optabs-query.c:476)
PR middle-end/84406
* optabs-query.c (find_widening_optab_handler_and_mode): If from_mode
is a scalar_int_mode, assert that to_mode is a scalar_int_mode with
greater precision. If to_mode is a MODE_PARTIAL_INT, stop the
search at the associated MODE_INT.
Jeff Law [Tue, 20 Feb 2018 18:59:22 +0000 (11:59 -0700)]
re PR middle-end/82123 (spurious -Wformat-overflow warning for converted vars)
PR middle-end/82123
PR tree-optimization/81592
PR middle-end/79257
* gimple-ssa-sprintf.c (format_integer): Query EVRP range analyzer
for range data rather than using global data.
* gcc.dg/pr81592.c: New test.
* gcc.dg/pr82123.c: New test.
Thomas Koenig [Tue, 20 Feb 2018 18:57:34 +0000 (18:57 +0000)]
re PR fortran/48890 ([F95] Wrong length of a character component of named constant derived-type)
2018-02-20 Thomas Koenig <tkoenig@gcc.gnu.org>
PR fortran/48890
PR fortran/83823
* primary.c (gfc_convert_to_structure_constructor):
For a constant string constructor, make sure the length
is correct.
2018-02-20 Thomas Koenig <tkoenig@gcc.gnu.org>
PR fortran/48890
PR fortran/83823
* gfortran.dg/structure_constructor_14.f90: New test.
Jeff Law [Tue, 20 Feb 2018 18:56:56 +0000 (11:56 -0700)]
re PR middle-end/82123 (spurious -Wformat-overflow warning for converted vars)
PR middle-end/82123
PR tree-optimization/81592
PR middle-end/79257
* gimple-ssa-sprintf.c (get_int_range): Query EVRP range analyzer for
range data rather than using global data.
Jeff Law [Tue, 20 Feb 2018 18:53:29 +0000 (11:53 -0700)]
re PR middle-end/82123 (spurious -Wformat-overflow warning for converted vars)
PR middle-end/82123
PR tree-optimization/81592
PR middle-end/79257
* gimple-ssa-sprintf.c (sprintf_dom_walker::handle_gimple_call): Query
the EVRP range analyzer for range data rather than using global data.
Jeff Law [Tue, 20 Feb 2018 18:52:07 +0000 (11:52 -0700)]
re PR middle-end/82123 (spurious -Wformat-overflow warning for converted vars)
PR middle-end/82123
PR tree-optimization/81592
PR middle-end/79257
* gimple-ssa-sprintf.c: Include alloc-pool.h, vr-values.h and
gimple-ssa-evrp-analyze.h
(class sprintf_dom_walker): Add after_dom_children member function.
Add evrp_range_analyzer member.
(sprintf_dom_walker::before_dom_children): Call into the EVRP
range analyzer as needed.
(sprintf_dom_walker::after_dom_children): New member function.
expand_call_mem_ref checks for TARGET_MEM_REFs that have compatible
type, but it didn't then go on to install the specific type we need,
which might have different alignment due to:
if (TYPE_ALIGN (type) != align)
type = build_aligned_type (type, align);
This was causing masked stores to be incorrectly marked as
aligned on AVX512.
2018-02-20 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
PR tree-optimization/84419
* internal-fn.c (expand_call_mem_ref): Create a TARGET_MEM_REF
with the required type if its current type is compatible but
different.
gcc/testsuite/
PR tree-optimization/84419
* gcc.dg/vect/pr84419.c: New test.
Ian Lance Taylor [Tue, 20 Feb 2018 13:52:56 +0000 (13:52 +0000)]
compiler: look through aliases for type compatibility
Aliases are supposed to be identical to the type being aliased, so
questions about type compatibility need to always ignore aliases,
except for error messages involving the type name.
The test case for this is https://golang.org/cl/94995.
The C++ frontend generates a break that results in the fallthrough
warning misfiring in nested switch blocks where cases in the inner
switch block return, rendering the break pointless. The fallthrough
detection in finish_break_stmt does not work either because the
condition is encoded as an IF_STMT and not a COND_EXPR.
Fix this by adding a condition for IF_STMT in the
langhooks.block_may_fallthru for C++. Fix tested on x86_64.
gcc/cp
* cp-objcp-common.c (cxx_block_may_fallthru): Add case for
IF_STMT.
gcc/testsuite
* g++.dg/nested-switch.C: New test case.
Jakub Jelinek [Tue, 20 Feb 2018 08:21:36 +0000 (09:21 +0100)]
re PR c++/84449 (ICE with constexpr and deleted destructor)
PR c++/84449
* tree.c (bot_manip): If build_cplus_new or break_out_target_exprs
returns error_mark_node, return it immediately.
(break_out_target_exprs): If cp_walk_tree with bot_manip returns
error_mark_node, return error_mark_node.
Paul Thomas [Mon, 19 Feb 2018 22:09:13 +0000 (22:09 +0000)]
re PR fortran/83344 (Use of uninitialized memory with ASSOCIATE and strings)
2018-02-19 Paul Thomas <pault@gcc.gnu.org>
PR fortran/83344
PR fortran/83975
* resolve.c (resolve_assoc_var): Rearrange the logic for the
determination of the character length of associate names. If
the associate name is missing a length expression or the length
expression is not a constant and the target is not a variable,
make the associate name allocatable and deferred length.
* trans-decl.c (gfc_get_symbol_decl): Null the character length
backend_decl for deferred length associate names that are not
variables. Set 'length' to gfc_index_zero_node for character
associate names, whose character length is a PARM_DECL.
2018-02-19 Paul Thomas <pault@gcc.gnu.org>
PR fortran/83344
PR fortran/83975
* gfortran.dg/associate_22.f90: Enable commented out test.
* gfortran.dg/associate_36.f90: New test.
Jakub Jelinek [Mon, 19 Feb 2018 19:16:26 +0000 (20:16 +0100)]
re PR c++/84448 (ICE with broken condition in parallel for loop)
PR c++/84448
* parser.c (cp_parser_binary_expression): For no_toplevel_fold_p, if
either operand is error_mark_node, set current.lhs to that instead of
creating a binary op with error_mark_node operands.
* gfortran.texi: Document additional src/dst_type. Fix some typos.
* trans-decl.c (gfc_build_builtin_function_decls): Declare the new
argument of _caf_*_by_ref () with * e { get, send, sendget }.
* trans-intrinsic.c (gfc_conv_intrinsic_caf_get): Add the type of the
data referenced when generating a call to caf_get_by_ref ().
(conv_caf_send): Same but for caf_send_by_ref () and
caf_sendget_by_ref ().
gcc/testsuite/ChangeLog:
2018-02-19 Andre Vehreschild <vehre@gcc.gnu.org>
* gfortran.dg/coarray_alloc_comp_6.f08: New test.
* gfortran.dg/coarray_alloc_comp_7.f08: New test.
* gfortran.dg/coarray_alloc_comp_8.f08: New test.
libgfortran/ChangeLog:
2018-02-19 Andre Vehreschild <vehre@gcc.gnu.org>
* caf/libcaf.h: Add type parameters to the caf_*_by_ref prototypes.
* caf/single.c (get_for_ref): Simplifications and now respecting
the type argument.
(_gfortran_caf_get_by_ref): Added source type handing to get_for_ref().
(send_by_ref): Simplifications and respecting the dst_type now.
(_gfortran_caf_send_by_ref): Added destination type hand over to
send_by_ref().
(_gfortran_caf_sendget_by_ref): Added general support and fixed stack
corruption. The function is now really usable.
Carl Love [Mon, 19 Feb 2018 17:27:39 +0000 (17:27 +0000)]
rs6000-builtin.def: Change NEG macro expansions from BU_ALTIVEC_A to BU_P8V_AV_1 and...
gcc/ChangeLog:
2018-02-19 Carl Love <cel@us.ibm.com>
* config/rs6000/rs6000-builtin.def: Change NEG macro expansions from
BU_ALTIVEC_A to BU_P8V_AV_1 and BU_ALTIVEC_OVERLOAD_1 to
BU_P8V_OVERLOAD_1.
* config/rs6000/rs6000-c.c: Change ALTIVEC_BUILTIN_VEC_NEG to
P8V_BUILTIN_VEC_NEG.
gcc/testsuite/ChangeLog:
2018-02-19 Carl Love <cel@us.ibm.com>
* gcc.target/powerpc/fold-vec-neg-int.p7.c: Remove test file.
Igor Tsimbalist [Mon, 19 Feb 2018 16:25:49 +0000 (17:25 +0100)]
CET shouldn't be enabled in 32-bit run-time libraries by defualt
ENDBR32 and RDSSPD are multi-byte NOPs on x86-64 processors and
newer x86 processors, starting Pentium Pro. They are UD on older
32-bit processors. Detect this at configure time and adjust the
default value for enable_cet. GCC will enable CET in 32-bit run-time
libraries in any case if --enable-cet is used to configure GCC.