5125 Commits

Author SHA1 Message Date
Jonathan Wakely
6e3647c98e libstdc++: Fix test that fails randomly [PR101866]
This test assumes that the same sequence of three values cannot occur,
which is incorect. It's unlikely, but not impossible.

Perform the check in a loop, so that in the unlikely event of an
identical sequence, we retry. If the library code is buggy it will keep
producing the same sequence and the test will time out. If the code is
working correctly then we will usually break out of the loop after one
iteration, or very rarely after two or three.

libstdc++-v3/ChangeLog:

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

(cherry picked from commit 93f1dbc7cdcc4b31ea4061efb4c2acf2d4f81eb8)
2021-08-11 23:50:33 +01:00
Jonathan Wakely
bde28c60c7 libstdc++: Fix create_directories to resolve symlinks [PR101510]
When filesystem__create_directories checks to see if the path already
exists and resolves to a directory, it uses filesystem::symlink_status,
which means it reports an error if the path is a symlink. It should use
filesystem::status, so that the target directory is detected, and no
error is reported.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit 124eaa50e0a34f5f89572c1aa812c50979da58fc)
2021-08-11 15:30:38 +01:00
Jonathan Wakely
c5f17274aa libstdc++: Add more tests for filesystem::create_directory [PR101510]
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit 0c4ae4ff46b1d7633f1e06f57d348b5817b8f640)
2021-08-11 15:30:38 +01:00
Jonathan Wakely
546cf31755 libstdc++: Implement LWG 3465 for std::compare_partial_order_fallback [PR101056]
libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit b76a529c095f076c4780df0c913cf6d2391bcbc9)
2021-08-11 15:30:38 +01:00
Jonathan Wakely
2fbb6039c5 libstdc++: Change [cmp.alg] assertions to constraints
This moves the same_as<decay_t<_Tp>, decay_t<_Up>> checks from the
[cmp.alg] function bodies into their constraints.

Also add a test for the compare_xxx_order_fallback algorithms.

libstdc++-v3/ChangeLog:

	* 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.

(cherry picked from commit e2c79b968ff95421c31a5a9a1b80b11321fe70d2)
2021-08-11 15:30:38 +01:00
Jonathan Wakely
63758bead0 libstdc++: Improve Doxygen documentation groups [PR 101258]
This defines some new Doxygen groups for C++17 variable templates and
for the contents of <experimental/type_traits>. By documenting the group
as a whole and adding each template to a group we don't need to document
them individually.

Also mark more internals with "@cond undocumented" so that Doxygen
ignores them by default. Also make Doxygen process <experimental/simd>.

For some reason, many of the class templates in <type_traits> do not
appear in the "Metaprogramming" group. For example, add_cv,
remove_extent, and all the is_xxx_constructible and is_xxx_assignable
traits. For some reason, Doxygen doesn't include them in the group,
despite doing it correctly for other traits in the same header.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/101258
	* doc/doxygen/user.cfg.in (INPUT): Add <experimental/simd>.
	(COLS_IN_ALPHA_INDEX): Remove obsolete tag.
	(PREDEFINED): Add/fix some more macros that need to be expanded.
	* include/bits/random.h: Stop Doxygen from documenting internal
	implementation details.
	* include/bits/random.tcc: Likewise.
	* include/bits/this_thread_sleep.h: Fix @file name.
	* include/experimental/bits/simd.h: Add to Doxygen group. Do not
	document internal implementation details.
	* include/experimental/bits/simd_detail.h: Do not document
	internal implementation details.
	* include/experimental/simd: Define Doxygen groups.
	* include/experimental/type_traits: Improve documentation for
	the header file. Define groups. Use @since commands.
	* include/std/scoped_allocator (scoped_allocator_adaptor): Move
	declaration before undocumented region.
	* include/std/type_traits (true_type, false_type): Use using
	declaration instead of typedef.
	(is_invocable_v, is_nothrow_invocable_v, is_invocable_r_v)
	(is_nothrow_invocable_r_v): Move definitions next to other C++17
	variable templates.
	Do not document internal implementation details. Move misplaced
	group-end command. Define group for variable templates.
	* include/std/variant: Do not document internal implementation
	details.
	* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
	line number.

(cherry picked from commit 6963c3b9ed1308bf5d2d8877956e56fec92853a7)
2021-08-11 15:30:37 +01:00
Jonathan Wakely
8000947e54 libstdc++: Fix some problems in PSTL tests
libstdc++-v3/ChangeLog:

	* 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.

(cherry picked from commit d1adbe5c1bd3f3ba098ff112eed9b61515e2dc20)
2021-07-19 11:57:23 +01:00
Jonathan Wakely
0e4fc87837 libstdc++: Remove precondition checks from ranges::subrange
The assertion in the subrange constructor causes semantic changes,
because the call to ranges::distance performs additional operations that
are not part of the constructor's specification. That will fail to
compile if the iterator is move-only, because the argument to
ranges::distance is passed by value. It will modify the subrange if the
iterator is not a forward iterator, because incrementing the copy also
affects the _M_begin member. Those problems could be prevented by using
if-constexpr to only do the assertion for copyable forward iterators,
but the call to ranges::distance can also prevent the constructor being
usable in constant expressions. If the member initializers are usable in
constant expressions, but iterator increments of equality comparisons
are not, then the checks done by __glibcxx_assert might
make constant evaluation fail.

This change removes the assertion. Additionally, a new typedef is
introduced to simplify the declarations using __make_unsigned_like_t on
the iterator's difference type.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/bits/ranges_util.h (subrange): Add __size_type typedef
	and use it to simplify declarations.
	(subrange(i, s, n)): Remove assertion.
	* testsuite/std/ranges/subrange/constexpr.cc: New test.

(cherry picked from commit a88fc03ba7e52d9a072f25d42bb9619fedb7892e)
2021-07-19 11:56:50 +01:00
Jonathan Wakely
6dc150d9a0 libstdc++: Fix std::get<T> for std::tuple [PR101427]
The std::get<T> functions relied on deduction failing if more than one
base class existed for the type T.  However the implementation of Core
DR 2303 (in r11-4693) made deduction succeed (and select the
more-derived base class).

This rewrites the implementation of std::get<T> to explicitly check for
more than one occurrence of T in the tuple elements, making it
ill-formed again. Additionally, the large wall of overload resolution
errors described in PR c++/101460 is avoided by making std::get<T> use
__get_helper<I> directly instead of calling std::get<I>, and by adding a
deleted overload of __get_helper<N> for out-of-range N.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/101427
	* include/std/tuple (tuple_element): Improve static_assert text.
	(__get_helper): Add deleted overload.
	(get<i>(tuple<T...>&&), get<i>(const tuple<T...>&&)): Use
	__get_helper directly.
	(__get_helper2): Remove.
	(__find_uniq_type_in_pack): New constexpr helper function.
	(get<T>): Use __find_uniq_type_in_pack and __get_helper instead
	of __get_helper2.
	* testsuite/20_util/tuple/element_access/get_neg.cc: Adjust
	expected errors.
	* testsuite/20_util/tuple/element_access/101427.cc: New test.

(cherry picked from commit 17855eed7fc76b2cee7fbbc26f84d3c8b99be13c)
2021-07-19 11:54:35 +01:00
Jonathan Wakely
ee22bc201e libstdc++: Fix noexcept-specifier for ranges::empty
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

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

(cherry picked from commit f9598d89a9f5a327ecdfa6f6978a0cfbe4447111)
2021-07-15 20:53:25 +01:00
Jonathan Wakely
df115674b3 libstdc++: Constrain std::as_writable_bytes [PR101411]
The std::as_writable_bytes function should be constrained to only accept
writable spans. Currently it can be called but then gives an error in
the function body.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

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

(cherry picked from commit 9d4393af9d2b37b78eb5b1f84f5d4da3a6f7fba6)
2021-07-14 15:59:49 +01:00
Patrick Palka
927548b42c libstdc++: Reduce ranges::minmax/minmax_element comparison complexity
This rewrites ranges::minmax and ranges::minmax_element so that it
performs at most 3*N/2 many comparisons, as required by the standard.
In passing, this also fixes PR100387 by avoiding a premature std::move
in ranges::minmax and in std::shift_right.

	PR libstdc++/100387

libstdc++-v3/ChangeLog:

	* 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.

(cherry picked from commit cc9c94d43dcfa98436152af9c00f011e9dab25f6)
2021-07-13 09:53:27 -04:00
Thomas Rodgers
c24384efbb libstdc++: Fix for deadlock in std::counting_semaphore [PR100806]
libstdc++-v3/ChangeLog:
	PR libstdc++/100806
	* include/bits/semaphore_base.h (__atomic_semaphore::_M_release):
	Force _M_release() to wake all waiting threads.
	* testsuite/30_threads/semaphore/100806.cc: New test.

(cherry picked from commit e02840c1a92abecd211ffaf05b28329bcb534583)
2021-06-22 11:07:58 -07:00
Jonathan Wakely
fe918041ce libstdc++: Replace incorrect static assertion in std::reduce [PR95833]
The standard does not require the iterator's value type to be
convertible to the result type, it only requires that the result of
dereferencing the iterator can be passed to the binary function.

libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit 0532452dcd17910dfd3d2b0df50dfe3ef1194bf7)
2021-06-18 16:55:09 +01:00
Jonathan Wakely
956077257a libstdc++: Suppress -Wstringop-overread warning in test
When compiled with -m32 -O2 -D_GLIBCXX_USE_CXX11_ABI=0 we get a warning
for 21_strings/basic_string/cons/char/1.cc:

bits/char_traits.h:409:56: warning: ‘void* __builtin_memcpy(void*, const void*, unsigned int)’ reading 1073741821 bytes from a region of size 19 [-Wstringop-overread]

The warning is legitimate, even if that line cannot be reached because
we throw std::length_error before getting there. Since the invalid
length is deliberate (and mentioned in a comment) just suppress the
warning, so that the test can verify we get the exception.

Also remove an unused typedef that produces another warning.

libstdc++-v3/ChangeLog:

	* testsuite/21_strings/basic_string/cons/char/1.cc: Use
	diagnostic pragma to suppress -Wstringop-overread error.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
(cherry picked from commit 92edc4a7684cdad5d30e197b976c35b2257f7bed)
2021-06-18 11:16:58 +01:00
Patrick Palka
f0d8d001d9 libstdc++: Non-triv-copyable extra args aren't simple [PR100940]
This force-enables perfect forwarding call wrapper semantics whenever
the extra arguments of a partially applied range adaptor aren't all
trivially copyable, so as to avoid incurring unnecessary copies of
potentially expensive-to-copy objects (such as std::function objects)
when invoking the adaptor.

	PR libstdc++/100940

libstdc++-v3/ChangeLog:

	* include/std/ranges (__adaptor::_Partial): For the "simple"
	forwarding partial specializations, also require that
	the extra arguments are trivially copyable.
	* testsuite/std/ranges/adaptors/100577.cc (test04): New test.

(cherry picked from commit 2b87f3318cf6334a3a42dcf27f2fdec0fce04665)
2021-06-17 22:55:34 -04:00
Patrick Palka
bc7a522548 libstdc++: Refine range adaptors' "simple extra args" mechanism [PR100940]
The _S_has_simple_extra_args mechanism is used to simplify forwarding
of range adaptor's extra arguments when perfect forwarding call wrapper
semantics isn't required for correctness, on a per-adaptor basis.
Both views::take and views::drop are flagged as such, but it turns out
perfect forwarding semantics are needed for these adaptors in some
contrived cases, e.g. when their extra argument is a move-only class
that's implicitly convertible to an integral type.

To fix this, we could just clear the flag for views::take/drop as with
views::split, but that'd come at the cost of acceptable diagnostics
for ill-formed uses of these adaptors (see PR100577).

This patch instead allows adaptors to parameterize their
_S_has_simple_extra_args flag according the types of the captured extra
arguments, so that we could conditionally disable perfect forwarding
semantics only when the types of the extra arguments permit it.  We
then use this finer-grained mechanism to safely disable perfect
forwarding semantics for views::take/drop when the extra argument is
integer-like, rather than incorrectly always disabling it.  Similarly,
for views::split, rather than always enabling perfect forwarding
semantics we now safely disable it when the extra argument is a scalar
or a view, and recover good diagnostics for these common cases.

	PR libstdc++/100940

libstdc++-v3/ChangeLog:

	* include/std/ranges (__adaptor::_RangeAdaptor): Document the
	template form of _S_has_simple_extra_args.
	(__adaptor::__adaptor_has_simple_extra_args): Add _Args template
	parameter pack.  Try to treat _S_has_simple_extra_args as a
	variable template parameterized by _Args.
	(__adaptor::_Partial): Pass _Arg/_Args to the constraint
	__adaptor_has_simple_extra_args.
	(views::_Take::_S_has_simple_extra_args): Templatize according
	to the type of the extra argument.
	(views::_Drop::_S_has_simple_extra_args): Likewise.
	(views::_Split::_S_has_simple_extra_args): Define.
	* testsuite/std/ranges/adaptors/100577.cc (test01, test02):
	Adjust after changes to _S_has_simple_extra_args mechanism.
	(test03): Define.

(cherry picked from commit 0f4a2fb44dad6c9c140226fc19ed16109b85e6f4)
2021-06-17 22:55:34 -04:00
Jonathan Wakely
3ae416e0a7 libstdc++: Fix common_reference for non-reference results [PR100894]
The result of COMMON-REF(A&, B&&) where they have no common reference
type should be ill-formed. Our implementation fails to check that the
COMMON-REF result is a reference, so is well-formed when it shouldn't
be. This means that common_reference uses that result when it shouldn't
do.

The fix is to reject the result of COMMON-REF(A, B) if it's not a
reference, so that common_reference falls through to the next case,
which uses COND-RES, which yields the correct non-reference result.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit c37b5ddcc88e0cc0f6a4ad609eda51021df0f6bb)
2021-06-14 21:34:33 +01:00
Jonathan Wakely
ded9ba1c06 libstdc++: Only run Filesystem TS test if supported
libstdc++-v3/ChangeLog:

	* testsuite/experimental/filesystem/path/native/conv_c++23.cc:
	Add dg-require-filesystem-ts directive.

(cherry picked from commit a40d2293a7a417fc7711f8f4e52dbd4c48c2a43f)
2021-06-14 15:11:27 +01:00
Jonathan Wakely
028fd30231 libstdc++: Fix std::any constraints [PR101034]
PR libstdc++/101034

libstdc++-v3/ChangeLog:

	* 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.

(cherry picked from commit 14f26c75d255ef05b706a12d25b003da8a2f5b45)
2021-06-14 15:11:22 +01:00
Jonathan Wakely
2280fbfa46 libstdc++: Add explicit -std=gnu++17 option to test
This test has no -std option so when the testsuite is run with
-std=gnu++20 or later, this test will use that. The recent addition of
no_unique_address will cause it to FAIL, because that's a reserved word
after C++17. Add an explicit option, so that this test alays uses
exactly C++17.

libstdc++-v3/ChangeLog:

	* testsuite/17_intro/headers/c++2017/all_attributes.cc: Add
	-std=gnu++17 option.

(cherry picked from commit 45fb3d45a4d4b79a00c56fa93e9e69d9d7762ca0)
2021-06-14 14:09:07 +01:00
Jonathan Wakely
c4f1bbed3d libstdc++: Use reserved name for attribute [PR101055]
The no_unique_address attribute is not a reserved name until C++20, so
to use it in C++11/14/17 modes we should use the __no_unique_address_
form. We already use that form when using the attribute, but not in the
__has_cpp_attribute check.

libstdc++-v3/ChangeLog:

	PR libstdc++/101055
	* include/std/tuple: Use reserved form of attribute name.
	* testsuite/17_intro/headers/c++2011/all_attributes.cc: Add
	check for no_unique_address.
	* testsuite/17_intro/headers/c++2014/all_attributes.cc:
	Likewise.
	* testsuite/17_intro/headers/c++2017/all_attributes.cc:
	Likewise.

(cherry picked from commit 917efba2dd4ff34336d0d3aa55285ae22503e4aa)
2021-06-14 12:10:52 +01:00
Patrick Palka
258aedd9ad libstdc++: Fix up semiregular-box partial specialization [PR100475]
This makes the in-place constructor of our partial specialization of
__box for already-semiregular types perform direct-non-list-initialization
(in accordance with the specification of the primary template), and
additionally makes the member function data() use std::__addressof.

libstdc++-v3/ChangeLog:

	PR libstdc++/100475
	* include/std/ranges (__box::__box): Use non-list-initialization
	in member initializer list of in-place constructor of the
	partial specialization for semiregular types.
	(__box::operator->): Use std::__addressof.
	* testsuite/std/ranges/adaptors/detail/semiregular_box.cc
	(test02): New test.
	* testsuite/std/ranges/single_view.cc (test04): New test.

(cherry picked from commit fe993b469c528230d9a01e1ae2208610f960dd9f)
2021-06-13 23:19:49 -04:00
Jonathan Wakely
828cdc6429 libstdc++: Fix filesystem::path comparisons for C++23
In C++23 there is a basic_string_view(Range&&) constructor, which is
constrained to take a range (specifically, a contiguous_range). When the
filesystem::path comparison operators call lhs.compare(rhs) the overload
taking a string_view is considered, which means checking whether path
satisfies the range concept. That satisfaction result changes depending
whether path::iterator is complete, which is ill-formed; no diagnostic
required. To avoid the problem, this change ensures that the overload
resolution is performed in a context where path::iterator is complete
and the range concept is satisfied. (The result of overload resolution
is always that the compare(const path&) overload is the best match, but
we still have to consider the compare(basic_string_view<value_type>) one
to decide if it even participates in overload resolution).

For std::filesystem::path we can't define the comparison operators later
in the file, because they are hidden friends, so a new helper is
introduced that gets defined when everything else is complete.

For std::experimental::filesystem::path we can just move the definitions
of the comparison operators later in the file.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/bits/fs_path.h (operator==, operator<=>): Use new
	_S_compare function.
	(path::_S_compare): New function to call path::compare in a
	context where path::iterator is complete.
	* include/experimental/bits/fs_path.h (operator<, operator==):
	Define after path::iterator is complete.
	* testsuite/27_io/filesystem/path/native/conv_c++23.cc: New
	test.
	* testsuite/experimental/filesystem/path/native/conv_c++23.cc:
	New test.

(cherry picked from commit 1e690757d30775ed340a368b9a9463b2ad68de01)
2021-06-11 23:23:57 +01:00
Jonathan Wakely
ef636c0005 libstdc++: Finish implementing LWG 3413 for propagate_const
We already have conditional noexcept so this just constrains the
non-member swap overload.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/experimental/propagate_const (swap): Constrain.
	* testsuite/experimental/propagate_const/swap/lwg3413.cc: New test.

(cherry picked from commit d319517e809ee50496db29e552f86a83a14c837c)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
e198d93d49 libstdc++: Fix constraint on std::optional assignment [PR 100982]
libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit b3fce1bd45f72cc9e55fb7431762e92e30fefcf1)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
4f11586945 libstdc++: Constrain three-way comparison for std::optional [PR 98842]
The operator<=>(const optional<T>&, const U&) operator is supposed to be
constrained with three_way_comparable_with<U, T> so that it can only be
used when T and U are weakly-equality-comparable and also three-way
comparable.

Adding that constrain completely breaks std::optional comparisons,
because it causes constraint recursion. To avoid that, an additional
check that U is not a specialization of std::optional is needed. That
appears to be a defect in the standard and should be reported to LWG.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit adec14811714e22a6c1f7f0199adc05370f0d8b0)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
2ba1680d3e libstdc++: Fix return type of ranges::ssize for 128-bit integer [PR 100824]
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/100824
	* include/bits/ranges_base.h (_SSize): Return signed type.
	* testsuite/std/ranges/access/ssize.cc: Check with __int128.

(cherry picked from commit 96963713f6a648a0ed890450e02ebdd8ff583b14)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
1112f1226a libstdc++: Implement LWG 3403 for std::ranges::ssize
I already changed the constraints for ranges::ssize to use ranges::size,
this implements the rest of LWG 3403, so that the returned type is the
signed type corresponding to the result of ranges::size.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/bits/ranges_base.h (_SSize): Return the result of
	ranges::size converted to the wider of make-signed-like-t<S> and
	ptrdiff_t, rather than the ranges different type.
	* testsuite/std/ranges/access/ssize.cc: Adjust expected result
	for an iota_view that uses an integer class type for its
	difference_type.

(cherry picked from commit 621ea10ca060ba19ec693aa73b5e29d553cca849)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
9505359158 libstdc++: Fix helper concept for ranges::data [PR 100824]
We need to decay the result of t.data() before checking if it's a
pointer.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/100824
	* include/bits/ranges_base.h (__member_data): Use __decay_copy.
	* testsuite/std/ranges/access/data.cc: Add testcase from PR.

(cherry picked from commit 3e5f2425f80aedd00f28235022a2755eb46f310d)
2021-06-11 23:23:56 +01:00
Jonathan Wakely
a842cb9c25 libstdc++: Fix value categories used by ranges access CPOs [PR 100824]
The implementation of P2091R0 was incomplete, so that some range access
CPOs used perfect forwarding where they should not. This fixes it by
consistently operating on lvalues.

Some additional changes that are not necessary to fix the bug:

Modify the __as_const helper to simplify its usage. Instead of deducing
the value category from its argument, and requiring callers to forward
the argument as the correct category, add a non-deduced template
parameter which is used for the value category and accept the argument
as an lvalue. This means callers say __as_const<T>(t) instead of
__as_const(std::forward<T>(t)).

Always use an lvalue reference type as the template argument for the
_S_noexcept helpers, so that we only instantiate one specialization for
lvalues and rvalues of the same type.

Move some helper concepts and functions from namespace std::__detail
to ranges::__cust_access, to be consistent with the ranges::begin CPO.
This ensures that the __adl_begin concept and the _Begin::operator()
function are in the same namespace, so unqualified lookup is consistent
and the poison pills for begin are visible to both.

Simplified static assertions for arrays, because the expression a+0 is
already ill-formed for an array of incomplete type.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/100824
	* include/bits/iterator_concepts.h (__detail::__decay_copy)
	(__detail::__member_begin, __detail::__adl_begin): Move to
	namespace ranges::__cust_access.
	(__detail::__ranges_begin): Likewise, and rename to __begin.
	Remove redundant static assertion.
	* include/bits/ranges_base.h (_Begin, _End, _RBegin, _REnd):
	Use lvalue in noexcept specifier.
	(__as_const): Add non-deduced parameter for value category.
	(_CBegin, _CEnd, _CRBegin, _CREnd, _CData): Adjust uses of
	__as_const.
	(__member_size, __adl_size, __member_empty, __size0_empty):
	(__eq_iter_empty, __adl_data): Use lvalue objects in
	requirements.
	(__sentinel_size): Likewise. Add check for conversion to
	unsigned-like.
	(__member_data): Allow non-lvalue types to satisfy the concept,
	but use lvalue object in requirements.
	(_Size, _SSize): Remove forwarding to always use an lvalue.
	(_Data): Likewise. Add static assertion for arrays.
	* testsuite/std/ranges/access/cdata.cc: Adjust expected
	behaviour for rvalues. Add negative tests for ill-formed
	expressions.
	* testsuite/std/ranges/access/data.cc: Likewise.
	* testsuite/std/ranges/access/empty.cc: Adjust expected
	behaviour for rvalues.
	* testsuite/std/ranges/access/size.cc: Likewise.

(cherry picked from commit ee9548b36a7f17e8a63585b58f340c93dcba95d8)
2021-06-11 23:23:55 +01:00
Jonathan Wakely
3a401ff88a libstdc++: Add feature test macro for heterogeneous lookup in unordered containers
Also update the C++20 status docs.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* doc/xml/manual/status_cxx2020.xml:
	* doc/html/*: Regenerate.
	* include/bits/hashtable.h (__cpp_lib_generic_unordered_lookup):
	Define.
	* include/std/version (__cpp_lib_generic_unordered_lookup):
	Define.
	* testsuite/23_containers/unordered_map/operations/1.cc: Check
	feature test macro.
	* testsuite/23_containers/unordered_set/operations/1.cc:
	Likewise.

(cherry picked from commit f78f25f43864f38ae5a6a9fcce8f26c94fe45bcd)
2021-06-11 23:23:55 +01:00
Patrick Palka
80495610eb libstdc++: Simplify range adaptors' forwarding of bound args [PR100577]
r11-8053 rewrote the range adaptor implementation in conformance with
P2281R1, making partial application act like a SFINAE-friendly perfect
forwarding call wrapper.  Making SFINAE-friendliness coexist with
perfect forwarding here requires adding fallback deleted operator()
overloads (as described in e.g. section 5.5 of P0847R6).  But
unfortunately, as reported in PR100577, this necessary technique of
using of deleted overloads regresses diagnostics for ill-formed calls to
partially applied range adaptors in GCC.

Although GCC's diagnostics can arguably be improved here by having the
compiler explain why the other candidates weren't viable when overload
resolution selects a deleted candidate, we can also largely work around
this on the library side (and achieve more concise diagnostics than by
a frontend-side improvement alone) if we take advantage of the
observation that not all range adaptors need perfect forwarding call
wrapper semantics, in fact only views::split currently needs it, because
all other range adaptors either take no extra arguments or only
arguments that are expected to be freely/cheaply copyable, e.g. function
objects and integer-like types.  (The discussion section in P2281R1 goes
into detail about why views::split is special.)

To that end, this introduces opt-in flags for denoting a range adaptor
as having "simple" extra arguments (in the case of a range adaptor
non-closure) or having a "simple" call operator (in the case of a range
adaptor closure).  These flags are then used to conditionally simplify
the operator() for the generic _Partial and _Pipe class templates, down
from needing three overloads thereof (including one defined as deleted)
to just needing a single overload.  The end result is that diagnostic
quality is restored for all adaptors except for views::split, and
diagnostics for the adaptors are generally made more concise since
there's only a single _Partial/_Pipe overload to diagnose instead of
three of them.

libstdc++-v3/ChangeLog:

	PR libstdc++/100577
	* include/std/ranges (_RangeAdaptorClosure): Document
	_S_has_simple_call_op mechanism.
	(_RangeAdaptor): Document _S_has_simple_extra_args mechanism.
	(__closure_has_simple_call_op): New concept.
	(__adaptor_has_simple_extra_args): Likewise.
	(_Partial<_Adaptor, _Args...>): New partial specialization.
	(_Partial<_Adaptor, _Arg>): Likewise.
	(_Pipe<_Lhs, _Rhs>): Likewise.
	(views::_All::_S_has_simple_call_op): Define to true.
	(views::_Filter::_S_has_simple_extra_args): Likewise.
	(views::_Transform::_S_has_simple_extra_args): Likewise.
	(views::_Take::_S_has_simple_extra_args): Likewise.
	(views::_TakeWhile::_S_has_simple_extra_args): Likewise.
	(views::_Drop::_S_has_simple_extra_args): Likewise.
	(views::_DropWhile::_S_has_simple_extra_args): Likewise.
	(views::_Join::_S_has_simple_call_op): Likewise.
	(views::_Split): Document why we don't define
	_S_has_simple_extra_args to true for this adaptor.
	(views::_Common::_S_has_simple_call_op): Define to true.
	(views::_Reverse::_S_has_simple_call_op): Likewise.
	(views::_Elements::_S_has_simple_call_op): Likewise.
	* testsuite/std/ranges/adaptors/100577.cc: New test.

(cherry picked from commit 57ed620ebfa4275d04efeec973e88f506b0e3ba8)
2021-06-10 17:24:22 -04:00
Patrick Palka
a35c5a5fc3 libstdc++: Avoid hard error in ranges::unique_copy [PR100770]
Here, in the constexpr if condition within ranges::unique_copy, when
input_iterator<_Out> isn't satisfied we must avoid substituting into
iter_value_t<_Out> because the latter isn't necessarily well-formed
then.  To that end, this patch factors out the condition into a concept
and uses it throughout.

This patch also makes the definition of our testsuite
output_iterator_wrapper more minimal by setting its value_type, pointer
and reference member types to void.  This means our existing tests for
unique_copy already exercise the fix for this bug, so we don't need
to add another test.  The only other fallout of this testsuite iterator
change appears in std/ranges/range.cc, where the use of range_value_t
on a test_output_range is now ill-formed.

	PR libstdc++/100770

libstdc++-v3/ChangeLog:

	* 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.

(cherry picked from commit 0614bbbe59c6953e088cffa39dfe63d86fc1fa96)
2021-06-10 16:59:34 -04:00
Patrick Palka
c6ccaf17dd libstdc++: Fix access issue in iota_view::_Sentinel [PR100690]
libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit 317a38cd468d565dc8ce45c6da0dbccf38808f70)
2021-06-10 15:15:54 -04:00
Patrick Palka
048eb89a1e libstdc++: Implement LWG 3391 changes to move/counted_iterator::base()
libstdc++-v3/ChangeLog:

	* 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().

(cherry picked from commit 08f3287eefea1d7c244db795d018870e8148d1c8)
2021-06-10 14:58:53 -04:00
Patrick Palka
3b93d61be5 libstdc++: Fix access issue in elements_view::_Sentinel [PR100631]
In the earlier commit r12-854 I forgot to also rewrite the other operator-
overload in terms of the split-out member function _M_distance_from.

libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit 38751c4d5e15bd1c682ac4c868a2c4ce48ca5503)
2021-06-10 14:51:40 -04:00
Patrick Palka
fd4db3ddc3 libstdc++: Fix miscellaneous issues with elements_view::_Sentinel [PR100631]
libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit 2e2eef80ac0c21f9533e6791ccf5e29458cbb77c)
2021-06-10 14:51:40 -04:00
Patrick Palka
a50cc70f1b libstdc++: Implement missing P0896R4 changes to reverse_iterator [PR100639]
This implements the P0896R4 changes to reverse_iterator's member types
value_type, difference_type and reference in C++20 mode, which fixes
taking the reverse_iterator of an iterator with a non-integral
difference_type (such as iota_view<long long>).

libstdc++-v3/ChangeLog:

	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.

(cherry picked from commit d5cbe0f0d4b7bc11f80b2236521f90ec94e95767)
2021-06-10 14:37:29 -04:00
Thomas Rodgers
fe28c123db libstd++: Only support atomic_ref::wait tests which are always lockfree
Fixes a regression on arm32 targets.

libstdc++-v3/ChangeLog:
	* testsuite/29_atomics/atomic_ref/wait_notify.cc: Guard
	test logic with constexpr check for is_always_lock_free.

(cherry picked from commit eb3a3bb8ce4ce2420919d03a3e9f9a2a4297c4d3)
2021-06-09 13:47:15 -07:00
Thomas Rodgers
d746294538 libstdc++: Fix Wrong param type in :atomic_ref<_Tp*>::wait [PR100889]
libstdc++-v3/ChangeLog:

	PR libstdc++/100889
	* include/bits/atomic_base.h (atomic_ref<_Tp*>::wait):
	Change parameter type from _Tp to _Tp*.
	* testsuite/29_atomics/atomic_ref/wait_notify.cc: Extend
	coverage of types tested.

(cherry picked from commit 25e5ecdf82b49977e86bfaded236fb34af2705ed)
2021-06-08 16:01:48 -07:00
Jonathan Wakely
10c58754a8 libstdc++: Use __builtin_unreachable for constexpr assertions [PR 100676]
The current implementation of compile-time precondition checks causes
compilation to fail by calling a non-constexpr function declared at
block scope. This breaks the CUDA compiler, which wraps some libstdc++
headers in a pragma that declares everything as a __host__ __device__
function, but others are not wrapped and so everything is a __host__
function. The local declaration thus gets redeclared as two different
types of function, which doesn't work.

Just use __builtin_unreachable to make constant evaluation fail, instead
of the local function declaration. Also simplify the assertion macros,
which has the side effect of giving simpler compilation errors when
using Clang.

libstdc++-v3/ChangeLog:

	PR libstdc++/100676
	* include/bits/c++config (__glibcxx_assert_1): Rename to ...
	(__glibcxx_constexpr_assert): ... this.
	(__glibcxx_assert_impl): Use __glibcxx_constexpr_assert.
	(__glibcxx_assert): Define as either __glibcxx_constexpr_assert
	or __glibcxx_assert_impl.
	(__glibcxx_assert_2): Remove
	* include/debug/macros.h (_GLIBCXX_DEBUG_VERIFY_AT_F): Use
	__glibcxx_constexpr_assert instead of __glibcxx_assert_1.
	* testsuite/21_strings/basic_string_view/element_access/char/back_constexpr_neg.cc:
	Adjust expected error.
	* testsuite/21_strings/basic_string_view/element_access/char/constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/char/front_constexpr_neg.cc:
	Likewise.
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/back_constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/constexpr_neg.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc:
	Likewise.
	* testsuite/23_containers/span/back_neg.cc: Likewise.
	* testsuite/23_containers/span/front_neg.cc: Likewise.
	* testsuite/23_containers/span/index_op_neg.cc: Likewise.

(cherry picked from commit 6b42b5a8a207de5e021a2916281f46bcd60b20d2)
2021-06-02 14:43:20 +01:00
Jonathan Wakely
88ed4abb35 libstdc++: Fix return value of std::ranges::advance [PR 100833]
The three-argument form of ranges::advance is supposed to return the
difference between the second argument and the distance the iterator was
advanced. When a non-random-access iterator is not advanced (because it
already equals the sentinel) we were returning 0 rather than n - 0.

libstdc++-v3/ChangeLog:

	PR libstdc++/100833
	* include/bits/ranges_base.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.

(cherry picked from commit d8326291695c0f13124c232ddf4fd34e3310e649)
2021-06-02 14:43:20 +01:00
Jonathan Wakely
f2b76257e9 libstdc++: Change [range.iter.op] functions to function objects [PR 100768]
The standard specifies std::ranges::distance etc as function templates,
but it also requires them to not be found by ADL, and to suppress ADL
when normal unqualified lookup does find them. That means they need to
be function objects.

libstdc++-v3/ChangeLog:

	PR libstdc++/100768
	* include/bits/ranges_base.h (advance, distance, next, 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.

(cherry picked from commit a49a045b92f982f5617c3bbde97a33157237e25b)
2021-06-02 14:43:19 +01:00
David Edelsohn
15c41a11ee testuite: fix libtdc++ libatomic flags
Some ports require libatomic for atomic operations, at least for some
data types and widths.  The libstdc++ testsuite previously was updated
to link against libatomic, but the search path was hard-coded to
something that is not always correct, and the shared library search
path was not set.

The search path was hard-coded to the expected location of the
libatomic build directory relative to the libstdc++ testsuite
directory, but if one uses parallelism when invoking the libstdc++
testsuite, the tests are run in the "normalXX" sub-directories, for
which the hard-coded search path is incorrect. The path also is
incorrect for alternative multilib and tool options.

This patch adopts the logic from gcc/testsuite/lib/atomic-dg.exp to
search for the library and adds the logic to the libstdc++ testsuite
libatomic seatch path code.  Previously the libstdc++ testsuite atomic
tests failed depending on the build configuration and if a build of
libatomic was installed in the default search path.

Bootstrapped on powerpc-ibm-aix7.2.3.0.

libstdc++-v3/ChangeLog:

	* testsuite/lib/dg-options.exp (atomic_link_flags): New.
	(add_options_for_libatomic): Use atomic_link_flags.

(cherry picked from commit fb6b24c66ea5a2ccbf6fb9f299c20a69f962ac9b)
2021-05-28 16:52:32 -04:00
Patrick Palka
e1489a3d61 libstdc++: Implement P2328 changes to join_view
This implements the wording changes of P2328R0 "join_view should join
all views of ranges".

libstdc++-v3/ChangeLog:

	* include/std/ranges (__detail::__non_propating_cache): Define
	as per P2328.
	(join_view): Remove constraints on the value and reference types
	of the wrapped iterator type as per P2328.
	(join_view::_Iterator::_M_satisfy): Adjust as per P2328.
	(join_view::_Iterator::operator++): Likewise.
	(join_view::_M_inner): Use __non_propating_cache as per P2328.
	Remove now-redundant use of __maybe_present_t.
	* testsuite/std/ranges/adaptors/join.cc: Include <array>.
	(test10): New test.

(cherry picked from commit 237dde3d03c573eb13c0e765520ee4b713aa2c7e)
2021-05-28 10:29:47 -04:00
Patrick Palka
49f369fb33 libstdc++: Fix iterator caching inside range adaptors [PR100479]
This fixes two issues with our iterator caching as described in detail
in the PR.  Since we recently added the __non_propagating_cache class
template as part of r12-336 for P2328, this patch just rewrites the
problematic _CachedPosition partial specialization in terms of this
class template.

For the offset partial specialization, it's safe to propagate the cached
offset on copy/move, but we should still invalidate the cached offset in
the source object on move.

libstdc++-v3/ChangeLog:

	PR libstdc++/100479
	* include/std/ranges (__detail::__non_propagating_cache): Move
	definition up to before that of _CachedPosition.  Make base
	class _Optional_base protected instead of private.  Add const
	overload for operator*.
	(__detail::_CachedPosition): Rewrite the partial specialization
	for forward ranges as a derived class of __non_propagating_cache.
	Remove the size constraint on the partial specialization for
	random access ranges.  Add copy/move/copy-assignment/move-assignment
	members to the offset partial specialization for random
	access ranges that propagate the cached value but additionally
	invalidate it in the source object on move.
	* testsuite/std/ranges/adaptors/100479.cc: New test.

(cherry picked from commit 46ed811bcb4b86a81ef3d78ea8cfffc6cd043144)
2021-05-28 10:20:18 -04:00
Joern Rennecke
5f772bd984 libstdc++: Disable floating_to_chars.cc on 16 bit targets
This patch conditionally disables the compilation of floating_to_chars.cc
on 16 bit targets, thus fixing a build failure for these targets as
the POW10_SPLIT_2 array exceeds the maximum object size.

libstdc++-v3/
	PR libstdc++/100361
	* include/std/charconv (to_chars): Hide the overloads for
	floating-point types for 16 bit targets.
	* src/c++17/floating_to_chars.cc: Don't compile for 16 bit targets.
	* testsuite/20_util/to_chars/double.cc: Run this test only on
	size32plus targets.
	* testsuite/20_util/to_chars/float.cc: Likewise.
	* testsuite/20_util/to_chars/long_double.cc: Likewise.
2021-05-20 13:41:13 +01:00
Jonathan Wakely
f8d2cef5c5 libstdc++: Fix filesystem::path constraints for volatile [PR 100630]
The constraint check for filesystem::path construction uses
decltype(__is_path_src(declval<Source>())) which mean it considers
conversion from an rvalue.  When Source is a volatile-qualified type
it cannot use is_path_src(const Unknown&) because a const lvalue
reference can only bind to a non-volatile rvalue.

Since the relevant path members all have a const Source& parameter,
the constraint should be defined in terms of declval<const Source&>(),
not declval<Source>(). This avoids the problem of volatile-qualified
rvalues, because we no longer use an rvalue at all.

libstdc++-v3/ChangeLog:

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

(cherry picked from commit 45aa7a447652e8541cc381d7ab128544f81ed857)
2021-05-17 21:52:19 +01:00
Thomas Rodgers
2b57186100 libstdc++: Fix wrong thread waking on notify [PR100334]
Fixes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100334

libstdc++-v3/ChangeLog:
	* include/bits/atomic_wait.h (__waiter::_M_do_wait_v): loop
	until value change observed.
	(__waiter_base::_M_laundered): New member.
	(__waiter_base::_M_notify): Check _M_laundered to determine
	whether to wake one or all.
	(__detail::__atomic_compare): Return true if call to
	__builtin_memcmp() == 0.
	(__waiter_base::_S_do_spin_v): Adjust predicate.
	* testsuite/29_atomics/atomic/wait_notify/100334.cc: New
	test.

(cherry picked from commit 346cbaf57828aef190de93271c0eb3f10c9aca61)
2021-05-17 12:06:51 -07:00