The following patch attempts to implement the C++26 P3378R2 - constexpr
exception types paper.
This is quite complicated, because most of these classes which should
be constexpr-ized use solely or mostly out of line definitions in
libstdc++, both for historical, code size and dual ABI reasons, so that
one can throw these as exceptions between TUs with old vs. new (or vice
versa) ABIs.
For this reason, logic_error/runtime_error and classes derived from it
have the old ABI std::string object inside of them and the exported
APIs from libstdc++.so.6 ensure the right thing.
Now, because new invoked during constant evaluation needs to be deleted
during the same constant evaluation and can't leak into the constant
expressions, I think we don't have to use COW strings under the hood
(which aren't constexpr I guess because of reference counting/COW) and
we can use something else, the patch uses heap allocated std::string
object (where __cow_constexpr_string class has just a pointer to that).
As I think we still want to hide the ugly details if !consteval in the
library, the patch exports 8 __cow_string class symbols (6 existing which
were previously just not exported and 2 new ones) and if !consteval
calls those through extern "C" _Zmangled_name symbols. The functions
are always_inline.
And then logic_error etc. have for C++26 (precisely for
__cpp_lib_constexpr_exceptions >= 202502L) constexpr definitions of
cdtors/methods. This results in slightly larger code (a few insns at most)
at runtime for C++26, e.g. instead of calling say some logic error
cdtor/method with 2 arguments it calls some __cow_string one with 2
arguments but + 8 bytes pointer additions on both.
The patch also removes the __throw_format_error forward declaration
which apparently wasn't needed for anything as all __throw_format_error
users were either in <format> or included <format> before the uses,
reverts the
https://gcc.gnu.org/pipermail/libstdc++/2025-July/062598.html
patch and makes sure __throw_* functions (only those for exception types
which the P3378R2 or P3068R5 papers made constexpr usable and there are
actually constexpr/consteval uses of those) are constexpr for C++26
constexpr exceptions.
The patch does that by splitting the bits/functexcept.h header:
1) bits/functexcept.h stays for the __throw_* functions which are (at
least for now) never constexpr (the <ios>, <system_error>, <future>
and <functional> std::exception derived classes) or are never used
or never used in constexpr/consteval contexts (<exception>, <typeinfo>
std::exception derived classes and std::range_error).
2) bits/new_{throw,except}.h for __throw_bad_alloc/__throw_bad_array_new_length
and std::bad_alloc/std::bad_array_new_length (where <new> includes
<bits/new_except.h> and <bits/new_throw.h> as well for the C++26 constexpr
exceptions case)
3) for the most complicated <stdexcept> stuff, one header
addition to bits/stdexcept.h one header for the __throw_logic_error etc.
forward declarations, one header for the __throw_logic_error etc.
definitions and one header without header guards which will
depending on __glibcxx_exc_in_string include one or the other because
<string> vs. <string_view> vs. <stdexcept> have heavy interdependencies
2025-12-11 Jakub Jelinek <jakub@redhat.com>
PR libstdc++/121114
libstdc++-v3/
* include/bits/version.def: Implement C++26 P3378R2 - constexpr
exception types.
(constexpr_exceptions): Change value from 1 to 202502, remove
no_stdname and TODO comments.
* include/bits/version.h: Regenerate.
* src/c++11/cow-stdexcept.cc (__cow_string(const char*)): New
ctor.
(__cow_string::c_str()): New method.
* config/abi/pre/gnu.ver (GLIBCXX_3.4.35): Export 8 __cow_string
symbols.
* include/bits/new_except.h: New file.
* include/bits/new_throw.h: New file.
* include/bits/stdexcept_throw.h: New file.
* include/bits/stdexcept_throwdef.h: New file.
* include/bits/stdexcept_throwfwd.h: New file.
* include/std/stdexcept: Include bits/stdexcept_except.h and move
everything after <string> include except for std::range_error into
include/bits/stdexcept_except.h.
(std::range_error): If __cpp_lib_constexpr_exceptions >= 202502L
make all cdtors and methods constexpr.
* include/bits/stdexcept_except.h: New file.
* include/std/optional (__glibcxx_want_constexpr_exceptions): Define
before including bits/version.h.
(bad_optional_access::what): Make constexpr for
__cpp_lib_constexpr_exceptions >= 202502L.
(__throw_bad_optional_access): Likewise.
* include/std/expected (__glibcxx_want_constexpr_exceptions): Define
before including bits/version.h.
(bad_expected_access): Make cdtors and all methods constexpr for
__cpp_lib_constexpr_exceptions >= 202502L.
* include/std/format (__glibcxx_want_constexpr_exceptions): Define
before including bits/version.h.
(_GLIBCXX_CONSTEXPR_FORMAT_ERROR): Define and undef later.
(format_error): Use _GLIBCXX_CONSTEXPR_FORMAT_ERROR on ctors.
* include/std/variant (__glibcxx_want_constexpr_exceptions): Define
before including bits/version.h.
(_GLIBCXX_CONSTEXPR_BAD_VARIANT_ACCESS): Define and undef later.
(bad_variant_access): Use it on ctors and what() method.
(__throw_bad_variant_access): Use it here too.
* testsuite/18_support/exception/version.cc: Adjust expected
__cpp_lib_constexpr_exceptions value.
* testsuite/19_diagnostics/runtime_error/constexpr.cc: New test.
* testsuite/19_diagnostics/headers/stdexcept/version.cc: New test.
* testsuite/19_diagnostics/logic_error/constexpr.cc: New test.
* testsuite/20_util/expected/observers.cc (test_value_throw): Change
return type to bool from void, return true at the end, add test
to dereference what() first character. Make it constexpr for
__cpp_lib_constexpr_exceptions >= 202502L and add static_assert.
* testsuite/20_util/expected/version.cc: Add tests for
__cpp_lib_constexpr_exceptions value.
* testsuite/20_util/variant/constexpr.cc: For
__cpp_lib_constexpr_exceptions >= 202502L include <string>.
(test_get): New function if __cpp_lib_constexpr_exceptions >= 202502L,
assert calling it is true.
* testsuite/20_util/variant/version.cc: Add tests for
__cpp_lib_constexpr_exceptions value.
* testsuite/20_util/optional/constexpr/observers/3.cc: Include
testsuite_hooks.h.
(eat, test01): New functions. Assert test01() is true.
* testsuite/20_util/optional/version.cc: Add tests for
__cpp_lib_constexpr_exceptions value.
* include/std/future: Add #include <bits/functexcept.h>.
* include/std/shared_mutex: Include <bits/new_throw.h>.
* include/std/flat_map: Include <bits/stdexcept_throw.h> instead of
<bits/functexcept.h>.
* include/std/syncstream: Remove <bits/functexcept.h> include.
* include/std/flat_set: Likewise.
* include/std/bitset: Include <bits/stdexcept_throw.h> instead of
<bits/functexcept.h>.
* include/std/string_view: Don't include <bits/functexcept.h>, include
<bits/stdexcept_throw.h> early if __glibcxx_exc_in_string is not
defined and include <bits/stdexcept_throw.h> at the end of
the header again if __glibcxx_exc_in_string is 2 and C++26 constexpr
exceptions are enabled.
(__glibcxx_exc_in_string): Define if __glibcxx_exc_in_string wasn't
defined before including <bits/stdexcept_throw.h>.
* include/std/array: Include <bits/stdexcept_throw.h> instead of
<bits/functexcept.h>.
* include/std/inplace_vector: Likewise.
* include/std/string: Include <bits/stdexcept_except.h> and
<bits/stdexcept_throw.h> after bits/basic_string.tcc include if
C++26 constexpr exceptions are enabled and include
<bits/stdexcept_throw.h> instead of <bits/functexcept.h> early.
(__glibcxx_exc_in_string): Define early to 1, undefine at the end.
* include/std/deque: Include <bits/stdexcept_throw.h>.
* include/bits/new_allocator.h: Include <bits/new_throw.h> instead
of <bits/functexcept.h>.
* include/bits/stl_algobase.h: Remove <bits/functexcept.h> include.
* include/bits/stl_vector.h: Include <bits/stdexcept_throw.h> instead
of <bits/functexcept.h>.
* include/bits/memory_resource.h: Include <bits/new_throw.h> instead
of <bits/functexcept.h>.
* include/bits/functexcept.h: Guard everything after includes with
#if _GLIBCXX_HOSTED.
(__throw_bad_alloc, __throw_bad_array_new_length, __throw_logic_error,
__throw_domain_error, __throw_invalid_argument, __throw_length_error,
__throw_out_of_range, __throw_out_of_range_fmt, __throw_runtime_error,
__throw_overflow_error, __throw_underflow_error): Move declarations to
other headers - <bits/new_throw.h> and <bits/stdexcept_throwfwd.h>.
* include/bits/stl_map.h: Include <bits/stdexcept_throw.h> instead
of <bits/functexcept.h>.
* include/bits/hashtable_policy.h: Include <bits/stdexcept_throw.h>
instead of <bits/functexcept.h>.
* include/bits/formatfwd.h (std::__throw_format_error): Remove
declaration.
* include/bits/specfun.h: Include <bits/stdexcept_throw.h> instead of
<bits/functexcept.h>.
* include/bits/basic_ios.h: Include <bits/functexcept.h>.
* include/bits/locale_classes.h: Likewise.
* include/tr1/cmath: Include <bits/stdexcept_throw.h> instead of
<bits/functexcept.h>.
* include/tr1/memory: Remove <bits/functexcept.h> include.
* include/tr1/array: Include <bits/stdexcept_throw.h>.
* include/ext/vstring_util.h: Include <bits/stdexcept_throw.h> instead
of <bits/functexcept.h>.
* include/ext/bitmap_allocator.h: Include <bits/new_throw.h> instead
of <bits/functexcept.h>.
* include/ext/mt_allocator.h: Likewise.
* include/ext/malloc_allocator.h: Likewise.
* include/ext/debug_allocator.h: Include <bits/stdexcept_throw.h>
instead of <bits/functexcept.h>.
* include/ext/concurrence.h: Include <bits/exception_defines.h>
instead of <bits/functexcept.h>.
* include/ext/throw_allocator.h: Include <bits/new_throw.h> and
<bits/stdexcept_throw.h> instead of <bits/functexcept.h>.
* include/ext/string_conversions.h: Include <bits/stdexcept_throw.h>
instead of <bits/functexcept.h>.
* include/ext/pool_allocator.h: Include <bits/new_throw.h> instead
of <bits/functexcept.h>.
* include/ext/ropeimpl.h: Include <bits/stdexcept_throw.h> instead of
<bits/functexcept.h>.
* include/tr2/dynamic_bitset: Likewise.
* include/experimental/optional: Include <bits/exception_defines.h>
instead of <bits/functexcept.h>.
* include/Makefile.am (bits_freestanding): Add
${bits_srcdir}/{new,stdexcept}_{except,throw}.h
and ${bits_srcdir}/stdexcept_throw{fwd,def}.h.
* include/Makefile.in: Regenerate.
* src/c++17/floating_from_chars.cc: Remove <bits/functexcept.h>
include.
* src/c++11/regex.cc: Likewise.
* src/c++11/functexcept.cc: Likewise.
* src/c++11/snprintf_lite.cc: Include <bits/stdexcept_throw.h> instead
of <bits/functexcept.h>.
* src/c++11/thread.cc: Include <bits/functexcept.h>.
* testsuite/util/testsuite_hooks.h: Include <bits/stdexcept_throw.h>
instead of <bits/functexcept.h>.
* testsuite/util/io/verified_cmd_line_input.cc: Include
<bits/exception_defines.h> instead of <bits/functexcept.h>.
* testsuite/20_util/allocator/105975.cc: Expect different diagnostics
for C++26.
* testsuite/23_containers/inplace_vector/access/capacity.cc: Remove
#error, guard if consteval { return; } with
#ifndef __cpp_lib_constexpr_exceptions.
* testsuite/23_containers/inplace_vector/access/elem.cc: Likewise.
* testsuite/23_containers/inplace_vector/cons/1.cc: Likewise.
* testsuite/23_containers/inplace_vector/cons/from_range.cc: Likewise.
* testsuite/23_containers/inplace_vector/modifiers/single_insert.cc:
Likewise.
* testsuite/23_containers/inplace_vector/modifiers/assign.cc:
Likewise.
* testsuite/23_containers/inplace_vector/modifiers/multi_insert.cc:
Likewise.
* libsupc++/new: Include <bits/new_except.h>.
(std::bad_alloc, std::bad_array_new_length): Move defintion to
<bits/new_except.h>.
libgomp/
* omp.h.in: Include <bits/new_throw.h> instead of
<bits/functexcept.h>.
gcc/testsuite/
* g++.dg/tree-ssa/pr110819.C: Guard scan-tree-dump-not delete on
c++23_down and add comment explaining why C++26 fails that.
* g++.dg/tree-ssa/pr96945.C: Likewise.
* g++.dg/tree-ssa/pr109442.C: Likewise.
* g++.dg/tree-ssa/pr116868.C: Likewise.
* g++.dg/tree-ssa/pr58483.C: Likewise.
I've just created LWG 4295 proposing this change, and am implementing it
via this patch.
libstdc++-v3/ChangeLog:
* include/experimental/memory (swap, make_observer_ptr): Add
constexpr.
(operator==, operator!=, operator<, operator>, operator<=)
(operator>=): Likewise.
* testsuite/experimental/memory/observer_ptr/make_observer.cc:
Checks for constant evaluation.
* testsuite/experimental/memory/observer_ptr/relops/relops.cc:
Likewise.
* testsuite/experimental/memory/observer_ptr/swap/swap.cc:
Likewise.
Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>
These should have been unsigned, but the static assertions are only in
the public std::bit_ceil and std::bit_width functions, not the internal
__bit_ceil and __bit_width ones.
libstdc++-v3/ChangeLog:
* include/experimental/bits/simd.h (__find_next_valid_abi): Cast
__bit_ceil argument to unsigned.
* src/c++17/floating_from_chars.cc (__floating_from_chars_hex):
Cast __bit_ceil argument to unsigned.
* src/c++17/memory_resource.cc (big_block): Cast __bit_width
argument to unsigned.
This actually implements P3247R2 by deprecating the is_trivial type
trait.
libstdc++-v3/ChangeLog:
* include/std/type_traits: Deprecate is_trivial and
is_trivial_v.
* include/experimental/type_traits: Suppress the deprecation
warning.
* testsuite/20_util/is_trivial/requirements/explicit_instantiation.cc:
Amend the test to suppress the deprecation warning.
* testsuite/20_util/is_trivial/requirements/typedefs.cc:
Likewise.
* testsuite/20_util/is_trivial/value.cc: Likewise.
* testsuite/20_util/variable_templates_for_traits.cc: Likewise.
* testsuite/experimental/type_traits/value.cc: Likewise.
* testsuite/18_support/max_align_t/requirements/2.cc: Update the
test with P3247R2's new wording.
Signed-off-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
I noticed a -Wc++17-extensions warning due to use of if-constexpr in
std::experimental::filesystem::path, which was not protected by
diagnostic pragmas to disable the warning.
While adding the pragmas I noticed that other places in the same file
use tag dispatching and multiple overloads instead of if-constexpr.
Since we're already using it in that file, we might as well just use it
everywhere.
libstdc++-v3/ChangeLog:
* include/experimental/bits/fs_path.h (path::_Cvt): Refactor to
use if-constexpr.
(path::string(const Allocator&)): Likewise.
We don't need to use std::aligned_storage in std::any. We just need a
POD type of the right size. The void* union member already ensures the
alignment will be correct. Avoiding std::aligned_storage means we don't
need to suppress a -Wdeprecated-declarations warning.
libstdc++-v3/ChangeLog:
* include/experimental/any (experimental::any::_Storage): Use
array of unsigned char instead of deprecated
std::aligned_storage.
* include/std/any (any::_Storage): Likewise.
* testsuite/20_util/any/layout.cc: New test.
When the scope of a qualified name is the current instantiation, and
qualified lookup finds nothing at template definition time, then we
know it'll find nothing at instantiation time (unless the current
instantiation has dependent bases). So such qualified name lookup
failure can be diagnosed ahead of time as per [temp.res.general]/6.
This patch implements that, for qualified names of the form (where
the current instantiation is A<T>):
this->non_existent
a.non_existent
A::non_existent
typename A::non_existent
It turns out we already optimistically attempt qualified lookup of
seemingly every qualified name, even when it's dependently scoped, and
then suppress issuing a lookup failure diagnostic after the fact.
So implementing this is mostly a matter of restricting the diagnostic
suppression to "dependentish" scopes (i.e. dependent scopes or the
current instantiation with dependent bases), rather than suppressing
for any dependently-typed scope as we currently do.
The cp_parser_conversion_function_id change is needed to avoid regressing
lookup/using8.C:
using A<T>::operator typename A<T>::Nested*;
When looking up A<T>::Nested we consider it not dependently scoped since
we entered A<T> from cp_parser_conversion_function_id earlier. But this
A<T> is the implicit instantiation A<T> not the primary template type A<T>,
and so the lookup fails which we now diagnose. This patch works around
this by not entering the template scope of a qualified conversion
function-id in this case, i.e. if we're in an expression vs declaration
context, by seeing if the type already went through finish_template_type
with entering_scope=true.
gcc/cp/ChangeLog:
* decl.cc (make_typename_type): Restrict name lookup failure
punting to dependentish_scope_p instead of dependent_type_p.
* error.cc (qualified_name_lookup_error): Improve diagnostic
when the scope is the current instantiation.
* parser.cc (cp_parser_diagnose_invalid_type_name): Likewise.
(cp_parser_conversion_function_id): Don't call push_scope on
a template scope unless we're in a declaration context.
(cp_parser_lookup_name): Restrict name lookup failure
punting to dependentish_scope_p instead of depedent_type_p.
* semantics.cc (finish_id_expression_1): Likewise.
* typeck.cc (finish_class_member_access_expr): Likewise.
libstdc++-v3/ChangeLog:
* include/experimental/socket
(basic_socket_iostream::basic_socket_iostream): Fix typo.
* include/tr2/dynamic_bitset
(__dynamic_bitset_base::_M_is_proper_subset_of): Likewise.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/alignas18.C: Expect name lookup error for U::X.
* g++.dg/cpp0x/forw_enum13.C: Expect name lookup error for
D3::A and D4<T>::A.
* g++.dg/parse/access13.C: Declare A::E::V to avoid name lookup
failure and preserve intent of the test.
* g++.dg/parse/enum11.C: Expect extra errors, matching the
non-template case.
* g++.dg/template/crash123.C: Avoid name lookup failure to
preserve intent of the test.
* g++.dg/template/crash124.C: Likewise.
* g++.dg/template/crash7.C: Adjust expected diagnostics.
* g++.dg/template/dtor6.C: Declare A::~A() to avoid name lookup
failure and preserve intent of the test.
* g++.dg/template/error22.C: Adjust expected diagnostics.
* g++.dg/template/static30.C: Avoid name lookup failure to
preserve intent of the test.
* g++.old-deja/g++.other/decl5.C: Adjust expected diagnostics.
* g++.dg/template/non-dependent34.C: New test.
Reviewed-by: Jason Merrill <jason@redhat.com>
With the change to the AVX512 find_last_set implementation, the change
to AVX512 operator!= is unnecessary. However, the latter was not
producing optimal code and unnecessarily set the padding bits. In
theory, the compiler could determine that with the new !=
implementation, the bit operation for clearing the padding bits is a
no-op and can be elided.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/115454
* include/experimental/bits/simd_x86.h (_S_not_equal_to): Use
neq comparison instead of bitwise negation after eq.
(_S_find_last_set): Clear unused high bits before computing
bit_width.
* testsuite/experimental/simd/pr115454_find_last_set.cc: New
test.
A proprietary embedded operating system that uses clang as its primary
compiler ships headers that require __clang__ to be defined. Defining
that macro causes libstdc++ to adopt workarounds that work for clang
but that break for GCC.
So, introduce a _GLIBCXX_CLANG macro, and a convention to test for it
rather than for __clang__, so that a GCC variant that adds -D__clang__
to satisfy system headers can also -D_GLIBCXX_CLANG=0 to avoid
workarounds that are not meant for GCC.
I've left fast_float and ryu files alone, their tests for __clang__
don't seem to be harmful for GCC, they don't include bits/c++config,
and patching such third-party files would just make trouble for
updating them without visible benefit. pstl_config.h, though also
imported, required adjustment.
for libstdc++-v3/ChangeLog
* include/bits/c++config (_GLIBCXX_CLANG): Define or undefine.
* include/bits/locale_facets_nonio.tcc: Test for it.
* include/bits/stl_bvector.h: Likewise.
* include/c_compatibility/stdatomic.h: Likewise.
* include/experimental/bits/simd.h: Likewise.
* include/experimental/bits/simd_builtin.h: Likewise.
* include/experimental/bits/simd_detail.h: Likewise.
* include/experimental/bits/simd_x86.h: Likewise.
* include/experimental/simd: Likewise.
* include/std/complex: Likewise.
* include/std/ranges: Likewise.
* include/std/variant: Likewise.
* include/pstl/pstl_config.h: Likewise.
The special case for Clang in the trait producing a signed integer type
lead to the trait returning 'char' where it should have been 'signed
char'. This workaround was introduced because on Clang the return type
of vector compares was not convertible to '_SimdWrapper<
__int_for_sizeof_t<...' unless '__int_for_sizeof_t<char>' was an alias
for 'char'. In order to not rewrite the complete mask type code (there
is code scattered around the implementation assuming signed integers),
this needs to be 'signed char'; so the special case for Clang needs to
be removed.
The conversion issue is now solved in _SimdWrapper, which now
additionally allows conversion from vector types with compatible
integral type.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/115308
* include/experimental/bits/simd.h (__int_for_sizeof): Remove
special cases for __clang__.
(_SimdWrapper): Change constructor overload set to allow
conversion from vector types with integral conversions via bit
reinterpretation.
This resolves a regression on i686 that was introduced with
r15-429-gfb1649f8b4ad50.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/115247
* include/experimental/bits/simd.h (__as_vector): Don't use
vector_size(8) on __i386__.
(__vec_shuffle): Never return MMX vectors, widen to 16 bytes
instead.
(concat): Fix padding calculation to pick up widening logic from
__as_vector.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/114958
* include/experimental/bits/simd.h (__as_vector): Return scalar
simd as one-element vector. Return vector from single-vector
fixed_size simd.
(__vec_shuffle): New.
(__extract_part): Adjust return type signature.
(split): Use __extract_part for any split into non-fixed_size
simds.
(concat): If the return type stores a single vector, use
__vec_shuffle (which calls __builtin_shufflevector) to produce
the return value.
* include/experimental/bits/simd_builtin.h
(__shift_elements_right): Removed.
(__extract_part): Return single elements directly. Use
__vec_shuffle (which calls __builtin_shufflevector) to for all
non-trivial cases.
* include/experimental/bits/simd_fixed_size.h (__extract_part):
Return single elements directly.
* testsuite/experimental/simd/pr114958.cc: New test.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/114803
* include/experimental/bits/simd_builtin.h
(_SimdBase2::operator __vector_type_t): There is no __builtin()
function in _SimdWrapper, instead use its conversion operator.
* testsuite/experimental/simd/pr114803_vecbuiltin_cvt.cc: New
test.
Avoid
-Wnarrowing in C code;
-Wtautological-compare in unconditional static_assert (necessary for
faking a dependency on a template parameter)
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
* include/experimental/bits/simd.h: Ignore -Wnarrowing for
arm_neon.h.
(__int_for_sizeof): Replace tautological compare with checking
for invalid template parameter value.
* include/experimental/bits/simd_builtin.h (__extract_part):
Remove tautological compare by combining two static_assert.
This resolves failing tests in check-simd.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/114750
* include/experimental/bits/simd_builtin.h
(_SimdImplBuiltin::_S_load, _S_store): Fall back to copying
scalars if the memory type cannot be vectorized for the target.
This resolves further failures (-Wreturn-type warnings) and test
failures for where-* tests targeting AVX-512.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
* include/experimental/bits/simd_x86.h (_S_masked_unary):
Cast inputs < 16 bytes to 16 byte vectors before calling the
right subtraction builtin. Before returning, truncate to the
return vector type.
This resolves failures in the "expensive" where-* test of check-simd
when targeting AVX-512.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
* include/experimental/bits/simd_x86.h (_S_masked_unary): Call
the 4- and 8-byte variants of __builtin_ia32_subp[ds] without
rounding direction argument.
libstdc++-v3/ChangeLog:
* include/Makefile.am: Add simd_sve.h.
* include/Makefile.in: Add simd_sve.h.
* include/experimental/bits/simd.h: Add new SveAbi.
* include/experimental/bits/simd_builtin.h: Use
__no_sve_deduce_t to support existing Neon Abi.
* include/experimental/bits/simd_converter.h: Convert
sequentially when sve is available.
* include/experimental/bits/simd_detail.h: Define sve
specific macro.
* include/experimental/bits/simd_math.h: Fallback frexp
to execute sequntially when sve is available, to handle
fixed_size_simd return type that always uses sve.
* include/experimental/simd: Include bits/simd_sve.h.
* testsuite/experimental/simd/tests/bits/main.h: Enable
testing for sve128, sve256, sve512.
* include/experimental/bits/simd_sve.h: New file.
Signed-off-by: Srinivas Yadav Singanaboina <vasu.srinivasvasu.14@gmail.com>
The PR points out that the destructors all have incorrect
noexcept-specifiers.
libstdc++-v3/ChangeLog:
PR libstdc++/114152
* include/experimental/scope (scope_exit scope_fail): Make
destructor unconditionally noexcept.
(scope_sucess): Fix noexcept-specifier.
* testsuite/experimental/scopeguard/114152.cc: New test.
The bitwise operators for combining bitmask types such as std::launch
are not consistently annotated with noexcept, constexpr, and nodiscard.
This is the subject of LWG 3977, although the proposed resolution
doesn't work. We can make the changes in libstdc++ anyway though.
libstdc++-v3/ChangeLog:
* include/bits/atomic_base.h (operator|, operator&): Add
noexcept.
* include/bits/fs_fwd.h (operator&, operator|, operator^)
(operator~): Add nodiscard to overloads for copy_options, perms,
perm_options, and directory_options.
* include/bits/ios_base.h (operator&, operator|, operator^)
(operator~): Add nodiscard and noexcept to overloads for
_Ios_Fmtflags, _Ios_Openmode, and _Ios_Iostate.
(operator|=, operator&=, operator^=): Add constexpr for C++14.
* include/bits/regex_constants.h (operator&, operator|, operator^)
(operator~): Add nodiscard and noexcept to overloads for
syntax_option_type and match_flag_type.
(operator|=, operator&=, operator^=): Add noexcept.
* include/std/charconv (operator&, operator|, operator^)
(operator~): Add nodiscard to overloads for chars_format.
* include/std/future (operator&, operator|, operator^)
(operator~): Add nodiscard for overloads for launch.
(operator&=, operator|=, operator^=): Add constexpr for C++14.
* include/experimental/bits/fs_fwd.h (operator&, operator|)
(operator^, operator~): Add nodiscard to overloads for
copy_options, perms, and directory_options.
* testsuite/27_io/ios_base/types/fmtflags/bitmask_operators.cc:
Add dg-warning for nodiscard warnings.
* testsuite/27_io/ios_base/types/iostate/bitmask_operators.cc:
Likewise.
* testsuite/27_io/ios_base/types/openmode/bitmask_operators.cc:
Likewise.
* testsuite/27_io/filesystem/operations/bitmask_types.cc:
New test.
In C++20 it's deprecated for a [=] lambda capture to capture the 'this'
pointer. Using resize_and_overwrite with a lambda seems like overkill to
write three chars to the string anyway. Just resize the string and
overwrite the end of it directly.
libstdc++-v3/ChangeLog:
* include/experimental/internet (network_v4::to_string()):
Remove lambda and use of resize_and_overwrite.
These atomics cause linker errors on arm4t where __sync_synchronize is
not defined. For single-threaded targets we don't need the atomics.
libstdc++-v3/ChangeLog:
* include/experimental/io_context (io_context) [!_GLIBCXX_HAS_GTHREADS]:
Use a plain integer for _M_work_count for single-threaded
targets.
* include/experimental/memory_resource (__get_default_resource)
[!_GLIBCXX_HAS_GTHREADS]: Use unsynchronized type for
single-threaded targets.
* src/c++17/default_resource.h: Adjust preprocessor conditions
to match memory_resource.cc.
* src/c++17/memory_resource.cc [!_GLIBCXX_HAS_GTHREADS]
(atomic_mem_res): Use unsynchronized type for single-threaded
targets.
Some constexpr functions were inadvertently relying on relaxed constexpr
rules from later standards.
libstdc++-v3/ChangeLog:
* include/bits/chrono.h (duration_cast): Do not use braces
around statements for C++11 constexpr rules.
* include/bits/stl_algobase.h (__lg): Rewrite as a single
statement for C++11 constexpr rules.
* include/experimental/bits/fs_path.h (path::string): Use
_GLIBCXX17_CONSTEXPR not _GLIBCXX_CONSTEXPR for 'if constexpr'.
* include/std/charconv (__to_chars_8): Initialize variable for
C++17 constexpr rules.
We can't define endpoints and resolvers without the relevant OS support.
If IPPROTO_TCP and IPPROTO_UDP are both udnefined then we won't need
basic_endpoint and basic_resovler anyway, so make them depend on those
macros.
libstdc++-v3/ChangeLog:
PR libstdc++/100285
* include/experimental/internet [IPPROTO_TCP || IPPROTO_UDP]
(basic_endpoint, basic_resolver_entry, resolver_base)
(basic_resolver_results, basic_resolver): Only define if the tcp
or udp protocols will be defined.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/109822
* include/experimental/bits/simd_builtin.h (_S_store): Rewrite
to avoid casts to other vector types. Implement store as
succession of power-of-2 sized memcpy to avoid PR90424.
The call to the base implementation sometimes didn't find a matching
signature because the _Abi parameter of _SimdImpl* was "wrong" after
conversion. It has to call into <new ABI tag>::_SimdImpl instead of the
current ABI tag's _SimdImpl. This also reduces the number of possible
template instantiations.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/110054
* include/experimental/bits/simd_builtin.h (_S_masked_store):
Call into deduced ABI's SimdImpl after conversion.
* include/experimental/bits/simd_x86.h (_S_masked_store_nocvt):
Don't use _mm_maskmoveu_si128. Use the generic fall-back
implementation. Also fix masked stores without SSE2, which
were not doing anything before.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/110050
* include/experimental/bits/simd.h (__vectorized_sizeof): With
__have_neon_a32 only single-precision float works (in addition
to integers).
Move the std::search definition from stl_algo.h to stl_algobase.h and use
the later in <functional>.
For consistency also move std::__parallel::search and associated helpers from
<parallel/stl_algo.h> to <parallel/stl_algobase.h> so that std::__parallel::search
is accessible along with std::search.
libstdc++-v3/ChangeLog:
* include/bits/stl_algo.h
(std::__search, std::search(_FwdIt1, _FwdIt1, _FwdIt2, _FwdIt2, _BinPred)): Move...
* include/bits/stl_algobase.h: ...here.
* include/std/functional: Replace <stl_algo.h> include by <stl_algobase.h>.
* include/parallel/algo.h (std::__parallel::search<_FIt1, _FIt2, _BinaryPred>)
(std::__parallel::__search_switch<_FIt1, _FIt2, _BinaryPred, _ItTag1, _ItTag2>):
Move...
* include/parallel/algobase.h: ...here.
* include/experimental/functional: Remove <bits/stl_algo.h> and <parallel/algorithm>
includes. Include <bits/stl_algobase.h>.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/109822
* include/experimental/bits/simd.h (to_native): Use int NTTP
as specified in PTS2.
(to_compatible): Likewise. Add missing tag to call mask
generator ctor.
* testsuite/experimental/simd/pr109822_cast_functions.cc: New
test.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/109949
* include/experimental/bits/simd.h (__intrinsic_type): If
__ALTIVEC__ is defined, map gnu::vector_size types to their
corresponding __vector T types without losing unsignedness of
integer types. Also prefer long long over long.
* include/experimental/bits/simd_ppc.h (_S_popcount): Cast mask
object to the expected unsigned vector type.
On ARM NEON doesn't support double, so __is_intrinsic_type_v<double,
whatever> should say false (instead of being ill-formed).
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/109261
* include/experimental/bits/simd.h (__intrinsic_type):
Specialize __intrinsic_type<double, 8> and
__intrinsic_type<double, 16> in any case, but provide the member
type only with __aarch64__.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/109261
* include/experimental/bits/simd_neon.h (_S_reduce): Add
constexpr and make NEON implementation conditional on
not __builtin_is_constant_evaluated.
The constexpr API is only available with -std=gnu++XX (and proposed for
C++26). The proposal is to have the complete simd API usable in constant
expressions.
This patch resolves several issues with using simd in constant
expressions.
Issues why constant_evaluated branches are necessary:
* subscripting vector builtins is not allowed in constant expressions
* if the implementation needs/uses memcpy
* if the implementation would otherwise call SIMD intrinsics/builtins
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/109261
* include/experimental/bits/simd.h (_SimdWrapper::_M_set):
Avoid vector builtin subscripting in constant expressions.
(resizing_simd_cast): Avoid memcpy if constant_evaluated.
(const_where_expression, where_expression, where)
(__extract_part, simd_mask, _SimdIntOperators, simd): Add either
_GLIBCXX_SIMD_CONSTEXPR (on public APIs), or constexpr (on
internal APIs).
* include/experimental/bits/simd_builtin.h (__vector_permute)
(__vector_shuffle, __extract_part, _GnuTraits::_SimdCastType1)
(_GnuTraits::_SimdCastType2, _SimdImplBuiltin)
(_MaskImplBuiltin::_S_store): Add constexpr.
(_CommonImplBuiltin::_S_store_bool_array)
(_SimdImplBuiltin::_S_load, _SimdImplBuiltin::_S_store)
(_SimdImplBuiltin::_S_reduce, _MaskImplBuiltin::_S_load): Add
constant_evaluated case.
* include/experimental/bits/simd_fixed_size.h
(_S_masked_load): Reword comment.
(__tuple_element_meta, __make_meta, _SimdTuple::_M_apply_r)
(_SimdTuple::_M_subscript_read, _SimdTuple::_M_subscript_write)
(__make_simd_tuple, __optimize_simd_tuple, __extract_part)
(__autocvt_to_simd, _Fixed::__traits::_SimdBase)
(_Fixed::__traits::_SimdCastType, _SimdImplFixedSize): Add
constexpr.
(_SimdTuple::operator[], _M_set): Add constexpr and add
constant_evaluated case.
(_MaskImplFixedSize::_S_load): Add constant_evaluated case.
* include/experimental/bits/simd_scalar.h: Add constexpr.
* include/experimental/bits/simd_x86.h (_CommonImplX86): Add
constexpr and add constant_evaluated case.
(_SimdImplX86::_S_equal_to, _S_not_equal_to, _S_less)
(_S_less_equal): Value-initialize to satisfy constexpr
evaluation.
(_MaskImplX86::_S_load): Add constant_evaluated case.
(_MaskImplX86::_S_store): Add constexpr and constant_evaluated
case. Value-initialize local variables.
(_MaskImplX86::_S_logical_and, _S_logical_or, _S_bit_not)
(_S_bit_and, _S_bit_or, _S_bit_xor): Add constant_evaluated
case.
* testsuite/experimental/simd/pr109261_constexpr_simd.cc: New
test.
We never need to use std::make_unsigned in std::char_traits<char16_t>
and std::char_traits<char32_t> because <cstdint> guarantees to provide
the types we need, since r9-2028-g8ba7f29e3dd064.
Similarly, experimental::source_location can just assume uint_least32_t
is defined by <cstdint>.
libstdc++-v3/ChangeLog:
* include/bits/char_traits.h (char_traits<char16_t>): Do not
depend on _GLIBCXX_USE_C99_STDINT_TR1.
(char_traits<char32_t>): Likewise.
* include/experimental/source_location: Likewise.
On Solaris the in_addr struct contains a union and value-initializing it
does not make the s_addr member active. This means we can't access that
member later during constant evaluation.
Make the constructors explicitly set every member that we might want to
read later in constexpr member functions. This means even the default
constructor can only be constexpr for C++20, because we can't change the
active member of a union in older standards.
libstdc++-v3/ChangeLog:
PR libstdc++/109482
* include/experimental/internet (basic_endpoint::basic_endpoint()):
Ensure that the required union members are active. Only define
as constexpr for C++20 and later.
(basic_endpoint::basic_endpoint(const protocol_type&, port_type)):
Likewise.
* testsuite/experimental/net/internet/endpoint/cons.cc: Only
check constexpr default constructor for C++20 and later.
* testsuite/experimental/net/internet/endpoint/extensible.cc:
Likewise.
As pointed out in P2641R1, we can use GCC's __builtin_constant_p to
emulate the proposed std::is_active_member. This allows us to detect
which of the union members is active during constant evaluation, so we
don't need the extra bool data member. We still can't support constexpr
until C++20 though, as we need to change the active member during
constant evaluation.
libstdc++-v3/ChangeLog:
* include/experimental/internet (ip::basic_endpoint::_M_if_v6):
Revert change from member function to data member. Fix for
constant evaluation by detecting which union member is active.
(ip::basic_endpoint::resize): Revert changes to update _M_is_v6
flag.
Change ip::basic_endpoint to work in constant expressions, but only for
C++20 and later (due to the use of a union, which cannot change active
member in constexpr evaluation until C++20).
During constant evaluation we cannot inspect the common initial sequence
of basic_endpoint's union members to check whether sin_family == AF_INET
or AF_INET6. This means we need to store an additional boolean member
that remembers whether we have a v4 or v6 address. The address type can
change behind our backs if a user copies an address to the data()
pointer and then calls resize(n), so we need to inspect the sa_family_t
member in the union after a resize and update the boolean. POSIX only
guarantees that the sa_family_t member of each protocol-specific address
structure is at the same offset and of the same type, not that there is
a common initial sequence. The check in resize is done using memcmp, so
that we avoid accessing an inactive member of the union if the
sockaddr_in and sockaddr_in6 structures do not have a common initial
sequence that includes the sa_family_t member.
libstdc++-v3/ChangeLog:
* include/experimental/internet (ip::make_address): Implement
missing overload.
(ip::address_v4::broadcast()): Avoid undefined shift.
(ip::basic_endpoint): Fix member functions for constexpr.
(ip::basic_endpoint::_M_is_v6): Replace member function with
data member, adjust member functions using it.
(ip::basic_endpoint::resize): Update _M_is_v6 based on sockaddr
content.
* testsuite/experimental/net/internet/address/v4/cons.cc: Fix
constexpr checks to work in C++14.
* testsuite/experimental/net/internet/address/v4/creation.cc:
Likewise.
* testsuite/experimental/net/internet/endpoint/cons.cc:
Likewise.
* testsuite/experimental/net/internet/network/v4/cons.cc:
Likewise.
* testsuite/experimental/net/internet/network/v4/members.cc:
Likewise.
* testsuite/experimental/net/internet/endpoint/extensible.cc: New test.
