Per the standard, the return type of a generators ranges iterator op*
should be the reference type rather than the yielded type.

The yielded type was used here by mistake.

libstdc++-v3/ChangeLog:

	* include/std/generator (generator::_Iterator::operator*): Fix
	return type.
	* testsuite/24_iterators/range_generators/iter_deref_return.cc:
	New test.

libstdc++-v3/ChangeLog:

	* include/std/generator: Fix _V badname.

Rmove the dejagnu code for checking whether std::stacktrace is supported
and just use the new dg-require-cpp-feature-test directive to check for
__cpp_lib_stacktrace instead.

libstdc++-v3/ChangeLog:

	* testsuite/19_diagnostics/stacktrace/current.cc: Check for
	__cpp_lib_stacktrace instead of check for stacktrace ET.
	* testsuite/19_diagnostics/stacktrace/entry.cc: Likewise.
	* testsuite/19_diagnostics/stacktrace/hash.cc: Likewise.
	* testsuite/19_diagnostics/stacktrace/output.cc: Likewise.
	* testsuite/19_diagnostics/stacktrace/stacktrace.cc: Likewise.
	* testsuite/19_diagnostics/stacktrace/synopsis.cc: Likewise.
	* testsuite/19_diagnostics/stacktrace/version.cc: Likewise.
	* testsuite/23_containers/vector/debug/assign4_backtrace_neg.cc:
	Likewise.
	* testsuite/lib/libstdc++.exp (check_effective_target_stacktrace):
	Remove.

This adds a new dejagnu directive which can be used to make a test
depend on a feature test macro such as __cpp_lib_text_encoding. This is
mroe flexible than writing a new dg-require-xxx for each feature.

libstdc++-v3/ChangeLog:

	* testsuite/lib/dg-options.exp (dg-require-cpp-feature-test):
	New proc.
	* testsuite/lib/libstdc++.exp (check_v3_target_cpp_feature_test):
	New proc.
	* testsuite/std/text_encoding/cons.cc: Use new directive to skip
	the test if the __cpp_lib_text_encoding feature test macro is
	not defined.
	* testsuite/std/text_encoding/requirements.cc: Likewise.

This was a copy & paste error.

libstdc++-v3/ChangeLog:

	* testsuite/std/text_encoding/requirements.cc: #undef the
	correct macro.

This was just approved in Tokyo as a DR for C++23. It doesn't affect us
yet, because we don't implement the __cpp_lib_format_ranges features. We
can add the disabled specializations and add a testcase now though.

libstdc++-v3/ChangeLog:

	* include/std/format (formatter): Disable specializations that
	would allow sequences of narrow characters to be formatted as
	wchar_t without conversion, as per LWG 3944.
	* testsuite/std/format/formatter/lwg3944.cc: New test.

We already have __is_in_place_type_v for in_place_type_t so adding an
equivalent for in_place_index_t allows us avoid a class template
instantiation for the __not_in_place_tag constraint on the most
commonly-used std::variant::variant(T&&) constructor.

For in_place_type_t we also have a __is_in_place_type class template
defined in terms of the variable template, but that isn't actually used
anywhere. I'm not adding an equivalent for the new variable template,
because that wouldn't be used either.

For GCC 15 we should remove the unused __is_in_place_tag and
__is_in_place_type class templates.

libstdc++-v3/ChangeLog:

	* include/bits/utility.h (__is_in_place_index_v): New variable
	template.
	* include/std/variant (__not_in_place_tag): Define in terms of
	variable templates not a class template.

The difference between __type_identity_t and std::type_identity_t is
observable, as demonstrated in the PR. Nobody in LWG seems to think this
an example we should really care about, but it seems easy and harmless
to change this.

libstdc++-v3/ChangeLog:

	PR libstdc++/114400
	* include/std/string_view (operator==): Use std::type_identity_t
	in C++20 instead of our own __type_identity_t.

The allocator objects in container node handles were not being destroyed
after the node was re-inserted into a container. They are stored in a
union and so need to be explicitly destroyed when the node becomes
empty. The containers were zeroing the node handle's pointer, which
makes it empty, causing the handle's destructor to think there's nothign
to clean up.

Add a new member function to the node handle which destroys the
allocator and zeros the pointer. Change the containers to call that
instead of just changing the pointer manually.

We can also remove the _M_empty member of the union which is not
necessary.

libstdc++-v3/ChangeLog:

	PR libstdc++/114401
	* include/bits/hashtable.h (_Hashtable::_M_reinsert_node): Call
	release() on node handle instead of just zeroing its pointer.
	(_Hashtable::_M_reinsert_node_multi): Likewise.
	(_Hashtable::_M_merge_unique): Likewise.
	(_Hashtable::_M_merge_multi): Likewise.
	* include/bits/node_handle.h (_Node_handle_common::release()):
	New member function.
	(_Node_handle_common::_Optional_alloc::_M_empty): Remove
	unnecessary union member.
	(_Node_handle_common): Declare _Hashtable as a friend.
	* include/bits/stl_tree.h (_Rb_tree::_M_reinsert_node_unique):
	Call release() on node handle instead of just zeroing its
	pointer.
	(_Rb_tree::_M_reinsert_node_equal): Likewise.
	(_Rb_tree::_M_reinsert_node_hint_unique): Likewise.
	(_Rb_tree::_M_reinsert_node_hint_equal): Likewise.
	* testsuite/23_containers/multiset/modifiers/114401.cc: New test.
	* testsuite/23_containers/set/modifiers/114401.cc: New test.
	* testsuite/23_containers/unordered_multiset/modifiers/114401.cc: New test.
	* testsuite/23_containers/unordered_set/modifiers/114401.cc: New test.

This is needed to avoid errors outside the immediate context when
evaluating is_default_constructible_v<vector<T, A>> when A is not
default constructible.

To avoid diagnostic regressions for 23_containers/vector/48101_neg.cc we
need to make the std::allocator<cv T> partial specializations default
constructible, which they probably should have been anyway.

libstdc++-v3/ChangeLog:

	PR libstdc++/113841
	* include/bits/allocator.h (allocator<cv T>): Add default
	constructor to partial specializations for cv-qualified types.
	* include/bits/stl_vector.h (_Vector_impl::_Vector_impl()):
	Constrain so that it's only present if the allocator is default
	constructible.
	* include/bits/stl_bvector.h (_Bvector_impl::_Bvector_impl()):
	Likewise.
	* testsuite/23_containers/vector/cons/113841.cc: New test.

The preprocessor checks for __cplusplus in <bits/stl_construct.h> should
use the appropriate feature test macros instead of __cplusplus, namely
__glibcxx_raw_memory_algorithms and __cpp_constexpr_dynamic_alloc.

For the latter, we want to check the compiler macro not the library's
__cpp_lib_constexpr_dynamic_alloc, because the latter is not defined for
freestanding but std::construct_at needs to be.

libstdc++-v3/ChangeLog:

	* include/bits/stl_construct.h (destroy_at, construct_at): Guard
	with feature test macros instead of just __cplusplus.

Put the C++23 generator and tuple_like ones before the C++26 ones.

libstdc++-v3/ChangeLog:

	* include/bits/version.def (generator, tuple_like): Move earlier
	in the file.
	* include/bits/version.h: Regenerate.

Replace std::result_of with std::invoke_result, as specified in the
standard since C++17, to avoid deprecated warnings for std::result_of.

We don't have __invoke_result_t in C++11 mode, so add it as an alias
template for __invoke_result<>::type (which is what std::result_of uses
as its base class, so there's no change in functionality).

This fixes warnings given by Clang 18.

libstdc++-v3/ChangeLog:

	PR libstdc++/114394
	* include/std/functional (bind): Use __invoke_result_t instead
	of result_of::type.
	* include/std/type_traits (__invoke_result_t): New alias
	template.
	* testsuite/20_util/bind/ref_neg.cc: Adjust prune pattern.

_GLIBCXX_DEBUG has now fully N3344 compliant iterator checks, we can define
__cpp_lib_null_iterators macros like the normal mode.

libstdc++-v3/ChangeLog:

	* include/bits/version.def (null_iterators): Remove extra_cond.
	* include/bits/version.h: Regenerate.

The multiplication (4 * _M_t * __1p) can wraparound to zero if _M_t is
unsigned and 4 * _M_t wraps to zero. The third operand has type double,
so do the second multiplication first, so that we aren't multiplying
integers.

libstdc++-v3/ChangeLog:

	PR libstdc++/114359
	* include/bits/random.tcc (binomial_distribution::param_type):
	Ensure arithmetic is done as type double.
	* testsuite/26_numerics/random/binomial_distribution/114359.cc: New test.

libstdc++-v3/ChangeLog:

	PR libstdc++/101228
	* include/pstl/parallel_backend_tbb.h (TBB_SUPPRESS_DEPRECATED_MESSAGES):
	Define before including <tbb/task.h> then undef afterwards.

This is a generated header but regenerating it requires the manual step
of running 'make -C include update-version' in the libstdc++ build dir.
Make it regenerate automatically when --enable-maintainer-mode is used.

libstdc++-v3/ChangeLog:

	* include/Makefile.am [MAINTAINER_MODE]: Add target to
	automatically update <bits/version.h>.
	* include/Makefile.in: Regenerate.

gcc/ChangeLog:

	* doc/install.texi (Prerequisites): Document use of autogen for
	libstdc++.

There are several more sub-directories below 'src' now, with lots more
conveience libraries. Document them all as of GCC 14.

Also document how to regenerate the generated headers under include/bits
and how to update the tzdata.zi file.

libstdc++-v3/ChangeLog:

	* doc/xml/manual/build_hacking.xml: Document generated files.
	Update list of convenience libraries and sub-directories under
	the src directory.
	* doc/html/*: Regenerate.

These scripts both print "generated by $file, do not edit" header but
one of them prints the wrong filename. Use the built-in __file__
attribute to ensure it's correct.

contrib/ChangeLog:

	* unicode/gen_libstdcxx_unicode_data.py: Fix header of generated
	file to name the correct script.

libstdc++-v3/ChangeLog:

	* include/bits/text_encoding-data.h: Regenerate.
	* include/bits/unicode-data.h: Regenerate.
	* scripts/gen_text_encoding_data.py: Fix header of generated
	file to name the correct script.

This has been reported upstream.

libstdc++-v3/ChangeLog:

	* testsuite/util/pstl/test_utils.h: Fix typos in comments.

This doesn't cause a problem with GCC, but Clang correctly diagnoses a
bug in the code. The objects in the allocated storage need to begin
their lifetime before we start using them.

This change uses the allocator's construct function instead of using
std::construct_at directly, in order to support fancy pointers.

libstdc++-v3/ChangeLog:

	PR libstdc++/114367
	* include/bits/stl_bvector.h (_M_allocate): Use allocator's
	construct function to begin lifetime of words.

For Darwin, in order to allow uninstalled testing, we need to provide
a '-B' option pointing to each path containing an uninstalled library
that we are using (these get appended to the embedded runpaths).

This updates the version of the atomic_link_flags proc in the libstdc++
testsuite to do the same as the one in the GCC testsuite.

libstdc++-v3/ChangeLog:

	* testsuite/lib/dg-options.exp (atomic_link_flags): Emit a -B
	option for the path to the uninstalled libatomic.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>

Darwin has a separate debug linker, which is invoked when the command
line contains source files and debug is enabled.

Using /dev/null as the executable name does not, therefore, work when
debug is enabled, since the debug linker does not accept /dev/null as
a valid executable name.

The leads to incorrectly UNSUPPORTED testcases because of the unintended
error result from the test compilation.

The solution here is to use a temporary file that is deleted at the
end of the test (which is the mechanism used elsewhere)

libstdc++-v3/ChangeLog:

	* testsuite/lib/libstdc++.exp (v3_target_compile): Instead of
	/dev/null, use a temporary file for test executables on Darwin.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>

We shall be able to advance from a 0 offset a value-initialized iterator.

libstdc++-v3/ChangeLog:

	* include/debug/safe_iterator.tcc (_Safe_iterator<>::_M_can_advance):
	Accept 0 offset advance on value-initialized iterator.
	* testsuite/23_containers/vector/debug/n3644.cc: New test case.

Unordered container local_iterator range shall not contain any singular
iterator unless both iterators are both value-initialized.

libstdc++-v3/ChangeLog:

	* include/debug/safe_local_iterator.tcc
	(_Safe_local_iterator::_M_valid_range): Add _M_value_initialized and
	_M_singular checks.
	* testsuite/23_containers/unordered_set/debug/114316.cc: New test case.

Consider range of value-initialized iterators as valid and empty.

libstdc++-v3/ChangeLog:

	PR libstdc++/114316
	* include/debug/safe_iterator.tcc (_Safe_iterator<>::_M_valid_range):
	First check if both iterators are value-initialized before checking if
	singular.
	* testsuite/23_containers/set/debug/114316.cc: New test case.
	* testsuite/23_containers/vector/debug/114316.cc: New test case.

The fast path for "{}" format strings has a bug for negative integers
where the length passed to std::to_chars is too long.

libstdc++-v3/ChangeLog:

	PR libstdc++/114325
	* include/std/format (_Scanner::_M_scan): Pass correct length to
	__to_chars_10_impl.
	* testsuite/std/format/functions/format.cc: Check negative
	integers with empty format-spec.

Add the [[nodiscard]] attribute to several functions in <algorithm>.
These all have no side effects and are only called for their return
value (e.g. std::count) or produce a result that must not be discarded
for correctness (e.g. std::remove).

I was intending to add the attribute to a number of other functions like
std::copy_if, std::unique_copy, std::set_union, and std::set_difference.
I stopped when I noticed that MSVC doesn't use it on those functions,
which I suspect is because they're often used with an insert iterator
(e.g. std::back_insert_iterator). In that case it doesn't matter if
you discard the result, because you have the container to tell you how
many elements were copied to the output range.

libstdc++-v3/ChangeLog:

	* include/bits/stl_algo.h (find_end, all_of, none_of, any_of)
	(find_if_not, is_partitioned, partition_point, remove)
	(remove_if, unique, lower_bound, upper_bound, equal_range)
	(binary_search, includes, is_sorted, is_sorted_until, minmax)
	(minmax_element, is_permutation, clamp, find_if, find_first_of)
	(adjacent_find, count, count_if, search, search_n, min_element)
	(max_element): Add nodiscard attribute.
	* include/bits/stl_algobase.h (min, max, lower_bound, equal)
	(lexicographical_compare, lexicographical_compare_three_way)
	(mismatch): Likewise.
	* include/bits/stl_heap.h (is_heap, is_heap_until): Likewise.
	* testsuite/25_algorithms/equal/debug/1_neg.cc: Add dg-warning.
	* testsuite/25_algorithms/equal/debug/2_neg.cc: Likewise.
	* testsuite/25_algorithms/equal/debug/3_neg.cc: Likewise.
	* testsuite/25_algorithms/find_first_of/concept_check_1.cc:
	Likewise.
	* testsuite/25_algorithms/is_permutation/2.cc: Likewise.
	* testsuite/25_algorithms/lexicographical_compare/71545.cc:
	Likewise.
	* testsuite/25_algorithms/lower_bound/33613.cc: Likewise.
	* testsuite/25_algorithms/lower_bound/debug/irreflexive.cc:
	Likewise.
	* testsuite/25_algorithms/lower_bound/debug/partitioned_neg.cc:
	Likewise.
	* testsuite/25_algorithms/lower_bound/debug/partitioned_pred_neg.cc:
	Likewise.
	* testsuite/25_algorithms/minmax/3.cc: Likewise.
	* testsuite/25_algorithms/search/78346.cc: Likewise.
	* testsuite/25_algorithms/search_n/58358.cc: Likewise.
	* testsuite/25_algorithms/unique/1.cc: Likewise.
	* testsuite/25_algorithms/unique/11480.cc: Likewise.
	* testsuite/25_algorithms/upper_bound/33613.cc: Likewise.
	* testsuite/25_algorithms/upper_bound/debug/partitioned_neg.cc:
	Likewise.
	* testsuite/25_algorithms/upper_bound/debug/partitioned_pred_neg.cc:
	Likewise.
	* testsuite/ext/concept_checks.cc: Likewise.
	* testsuite/ext/is_heap/47709.cc: Likewise.
	* testsuite/ext/is_sorted/cxx0x.cc: Likewise.

For 80-bit long double we need to clear the padding bits on
construction.

libstdc++-v3/ChangeLog:

	* include/bits/atomic_base.h (__atomic_float::__atomic_float(Fp)):
	Clear padding.
	* testsuite/29_atomics/atomic_float/compare_exchange_padding.cc:
	New test.

Signed-off-by: xndcn <xndchn@gmail.com>

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

The bug with exceptions thrown during a std::call_once call affects all
targets, so fix the docs that say it only affects non-Linux targets.

libstdc++-v3/ChangeLog:

	PR libstdc++/66146
	* doc/xml/manual/status_cxx2011.xml: Remove mention of Linux in
	note about std::call_once.
	* doc/xml/manual/status_cxx2014.xml: Likewise.
	* doc/xml/manual/status_cxx2017.xml: Likewise.
	* doc/html/manual/status.html: Regenerate.

libstdc++-v3/ChangeLog:

	* doc/xml/manual/status_cxx2023.xml: Update C++23 status table.
	* doc/html/manual/status.html: Regenerate.
	* include/bits/version.def: Fix typo in comment.