Commit Graph

5185 Commits

Author SHA1 Message Date
Jonathan Wakely
8ed6cfbbee libstdc++: Fix non-default constructors for hash containers [PR101583]
When I added the new mixin to _Hashtable, I forgot to explicitly
construct it in each non-default constructor. That means you can't
use any constructors unless all three of the hash function, equality
function, and allocator are all default constructible.

libstdc++-v3/ChangeLog:

	PR libstdc++/101583
	* include/bits/hashtable.h (_Hashtable): Replace mixin with
	_Enable_default_ctor. Construct it explicitly in all
	non-forwarding, non-defaulted constructors.
	* testsuite/23_containers/unordered_map/cons/default.cc: Check
	non-default constructors can be used.
	* testsuite/23_containers/unordered_set/cons/default.cc:
	Likewise.
2021-07-22 19:39:58 +01:00
Jonathan Wakely
aca7a0253d libstdc++: Use std::addressof in ranges::uninitialized_xxx [PR101571]
Make the ranges::uninitialized_xxx algorithms use std::addressof to
protect against iterator types that overload operator&.

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

libstdc++-v3/ChangeLog:

	PR libstdc++/101571
	* include/bits/ranges_uninitialized.h (_DestroyGuard): Change
	constructor parameter to reference and use addressof.
	* testsuite/util/testsuite_iterators.h: Define deleted operator&
	overloads for test iterators.
2021-07-22 14:37:24 +01:00
Jonathan Wakely
8edb614205 libstdc++: Make __gnu_cxx::sequence_buffer move-aware [PR101542]
The PR explains that Clang trunk now selects a different constructor
when a non-const sequence_buffer is returned in a context where it
qualifies as an implicitly-movable entity. Because lookup is first
performed using an rvalue, the sequence_buffer(const sequence_buffer&)
constructor gets chosen, which makes a copy instead of a "pseudo-move"
via the sequence_buffer(sequence_buffer&) constructor. The problem isn't
seen with GCC because as noted in the r11-2412 commit log, GCC actually
implements a slightly modified rule that avoids breaking exactly this
type of code.

This patch adds a move constructor to sequence_buffer, so that implicit
or explicit moves will have the same effect, calling the
sequence_buffer(sequence_buffer&) constructor. A move assignment
operator is also added to make move assignment work similarly.

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

libstdc++-v3/ChangeLog:

	PR libstdc++/101542
	* include/ext/rope (sequence_buffer): Add move constructor and
	move assignment operator.
	* testsuite/ext/rope/101542.cc: New test.
2021-07-21 17:20:37 +01:00
Jonathan Wakely
124eaa50e0 libstdc++: Fix create_directories to resolve symlinks [PR101510]
When filesystem__create_directories checks to see if the path already
exists and resovles 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:
	* testsuite/27_io/filesystem/operations/create_directory.cc: Do
	not test with symlinks on Windows.
	* testsuite/experimental/filesystem/operations/create_directories.cc:
	* testsuite/experimental/filesystem/operations/create_directory.cc:
	Do not test with symlinks on Windows.
2021-07-20 20:34:47 +01:00
Jonathan Wakely
89ec3b67db libstdc++: fix is_default_constructible for hash containers [PR 100863]
The recent change to _Hashtable_ebo_helper for this PR broke the
is_default_constructible trait for a hash container with a non-default
constructible allocator. That happens because the constructor needs to
be user-provided in order to initialize the member, and so is not
defined as deleted when the type is not default constructible.

By making _Hashtable derive from _Enable_special_members we can ensure
that the default constructor for the std::unordered_xxx containers is
deleted when it would be ill-formed. This makes the trait give the
correct answer.

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

libstdc++-v3/ChangeLog:

	PR libstdc++/100863
	* include/bits/hashtable.h (_Hashtable): Conditionally delete
	default constructor by deriving from _Enable_special_members.
	* testsuite/23_containers/unordered_map/cons/default.cc: New test.
	* testsuite/23_containers/unordered_set/cons/default.cc: New test.
2021-07-20 16:22:26 +01:00
Jonathan Wakely
0c4ae4ff46 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.
2021-07-20 12:54:30 +01:00
Jonathan Wakely
3dbc7b809a libstdc++: Improve diagnostics for std::get with invalid tuple index
This adds a deleted overload of std::get<I>(const tuple<Types...>&).
Invalid calls with an out of range index will match the deleted overload
and give a single, clear error about calling a deleted function, instead
of overload resolution errors for every std::get overload in the
library.

This changes the current output of 15+ errors (plus notes and associated
header context) into just two errors (plus context):

error: static assertion failed: tuple index must be in range
error: use of deleted function 'constexpr std::__enable_if_t<(__i >= sizeof... (_Types))> std::get(const std::tuple<_Types ...>&) [with long unsigned int __i = 1; _Elements = {int}; std::__enable_if_t<(__i >= sizeof... (_Types))> = void]'

This seems like a nice improvement, although PR c++/66968 means that
"_Types" is printed in the signature rather than "_Elements".

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

libstdc++-v3/ChangeLog:

	* include/std/tuple (get<I>): Add deleted overload for bad
	index.
	* testsuite/20_util/tuple/element_access/get_neg.cc: Adjust
	expected errors.
2021-07-16 22:24:34 +01:00
Jonathan Wakely
95891ca020 libstdc++: Modernize <bits/random.h> helpers
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/bits/random.h (_Shift::__value): Use constexpr.
	(_Select_uint_least_t::type): Use using-declaration.
	(_Mod): Likewise.
	* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
	line number.
2021-07-16 15:03:03 +01:00
Patrick Palka
1af937eb62 libstdc++: invalid default init in _CachedPosition [PR101231]
The primary template for _CachedPosition is a dummy implementation for
non-forward ranges, the iterators for which generally can't be cached.
Because this implementation doesn't actually cache anything, _M_has_value
is defined to be false and so calls to _M_get (which are always guarded
by _M_has_value) are unreachable.

Still, to suppress a "control reaches end of non-void function" warning
I made _M_get return {}, but after P2325 input iterators are no longer
necessarily default constructible so this workaround now breaks valid
programs.

This patch fixes this by instead using __builtin_unreachable to squelch
the warning.

	PR libstdc++/101231

libstdc++-v3/ChangeLog:

	* include/std/ranges (_CachedPosition::_M_get): For non-forward
	ranges, just call __builtin_unreachable.
	* testsuite/std/ranges/istream_view.cc (test05): New test.
2021-07-16 09:44:42 -04:00
Patrick Palka
73464a472a libstdc++: Give split_view::_Sentinel a default ctor [PR101214]
This gives the new split_view's sentinel type a defaulted default
constructor, something which was overlooked in r12-1665.  This patch
also fixes a couple of other issues with the new split_view as reported
in the PR.

	PR libstdc++/101214

libstdc++-v3/ChangeLog:

	* include/std/ranges (split_view::split_view): Use std::move.
	(split_view::_Iterator::_Iterator): Remove redundant
	default_initializable constraint.
	(split_view::_Sentinel::_Sentinel): Declare.
	* testsuite/std/ranges/adaptors/split.cc (test02): New test.
2021-07-16 09:44:32 -04:00
Marek Polacek
e32234536f c++: Don't hide narrowing errors in system headers
Jonathan pointed me at this issue where

  constexpr unsigned f() { constexpr int n = -1; return unsigned{n}; }

is accepted in system headers, despite the narrowing conversion from
a constant.  I suspect that whereas narrowing warnings should be
disabled, ill-formed narrowing of constants should be a hard error
(which can still be disabled by -Wno-narrowing).

gcc/cp/ChangeLog:

	* typeck2.c (check_narrowing): Don't suppress the pedantic error
	in system headers.

libstdc++-v3/ChangeLog:

	* testsuite/20_util/ratio/operations/ops_overflow_neg.cc: Add
	dg-error.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1y/Wnarrowing2.C: New test.
	* g++.dg/cpp1y/Wnarrowing2.h: New test.
2021-07-16 09:28:37 -04:00
Jonathan Wakely
17855eed7f 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.
2021-07-15 16:25:42 +01:00
Jonathan Wakely
f9c2ce1dae libstdc++: Add noexcept-specifier to basic_string_view(It, End)
This adds a conditional noexcept to the C++20 constructor. The
std::to_address call cannot throw, so only taking the difference of the
two iterators can throw.

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

libstdc++-v3/ChangeLog:

	* include/std/string_view (basic_string_view(It, End)): Add
	noexcept-specifier.
	* testsuite/21_strings/basic_string_view/cons/char/range.cc:
	Check noexcept-specifier. Also check construction without CTAD.
2021-07-14 12:23:33 +01:00
Jonathan Wakely
9d4393af9d 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.
2021-07-12 18:35:27 +01:00
Jonathan Wakely
bc8f0ed704 libstdc++: Revert changes to std::unique_ptr<T[]>::operator[] [PR 101271]
This reverts the changes in r12-1778 which added a noexcept-specifier to
std::unique_ptr<T[]>::operator[], and the changes in r12-1844 which
tried to make it work with incomplete types (for PR 101236).

The noexcept-specifier is not required by the standard, and is causing
regressions, so just remove it.

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

libstdc++-v3/ChangeLog:

	PR libstdc++/101271
	* include/bits/unique_ptr.h (unique_ptr<T[],D>::operator[]):
	Remove noexcept-specifier.
	(unique_ptr<T[],D>::_S_nothrow_deref): Remove.
	* testsuite/20_util/unique_ptr/lwg2762.cc: Remove checks for
	operator[].
2021-07-02 12:15:28 +01:00
Jonathan Wakely
6963c3b9ed 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.
2021-07-01 00:25:46 +01:00
Jonathan Wakely
996be6b670 libstdc++: Suppress redundant definitions of static members in <random>
Since C++17 the static members of the random number engines are
implicitly inline, so don't need definitions.

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

libstdc++-v3/ChangeLog:

	* include/bits/random.tcc [__cpp_inline_variables]: Remove
	redundant definitions of static constexpr member variables.
	* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
	line number.
2021-07-01 00:15:29 +01:00
Jonathan Wakely
75f948f089 libstdc++: Fix backwards logic in 17_intro/names.cc test [PR 97088]
I meant to undef the names that clash with newlib headers for newlib,
but I only undef'd them for non-newlib targets. This means they still
cause errors for newlib, and aren't tested for other targets.

This fixes the test to check those names for non-newlib targets, and to
undef them to avoid errors for newlib.

libstdc++-v3/ChangeLog:

	PR libstdc++/97088
	* testsuite/17_intro/names.cc: Fix #if condition for names used
	by newlib headers.
2021-06-28 15:15:16 +01:00
Jonathan Wakely
b7a89c041a libstdc++: Allow unique_ptr<Incomplete[]>::operator[] [PR 101236]
PR libstdc++/101236 shows that LLVM depends on being able to use
unique_ptr<T[]>::operator[] when T is incomplete. This is undefined, but
previously worked with libstdc++. When I added the conditional noexcept
to that operator we started to diagnose the incomplete type.

This change restores support for that case, by making the noexcept
condition check that the type is complete before checking whether
indexing on the pointer can throw.  A workaround for PR c++/101239 is
needed to avoid a bogus error where G++ fails to do SFINAE on the
ill-formed p[n] expression and gets an ICE. Instead of checking that the
p[n] expression is valid in the trailing-return-type, we only check that
the element_type is complete.

libstdc++-v3/ChangeLog:

	PR libstdc++/101236
	* include/bits/unique_ptr.h (unique_ptr<T[], D>::operator[]):
	Fail gracefully if element_type is incomplete.
	* testsuite/20_util/unique_ptr/cons/incomplete.cc: Clarify that
	the standard doesn't require this test to work for array types.
	* testsuite/20_util/unique_ptr/lwg2762.cc: Check that incomplete
	types can be used with array specialization.
	* testsuite/20_util/unique_ptr/101236.cc: New test.
2021-06-28 14:20:55 +01:00
Jonathan Wakely
e5c422b7d8 libstdc++: Implement LWG 415 for std::ws
For C++11 std::ws changed to be an unformatted input function, meaning
it constructs a sentry and sets badbit on exceptions.

libstdc++-v3/ChangeLog:

	* doc/xml/manual/intro.xml: Document LWG 415 change.
	* doc/html/manual/bugs.html: Regenerate.
	* include/bits/istream.tcc (ws): Create sentry and catch
	exceptions.
	* testsuite/27_io/basic_istream/ws/char/lwg415.cc: New test.
	* testsuite/27_io/basic_istream/ws/wchar_t/lwg415.cc: New test.
2021-06-28 13:34:49 +01:00
Jonathan Wakely
f8c5b542f6 libstdc++: Implement LWG 581 for std:ostream::flush()
LWG 581 changed ostream::flush() to an unformatted output function for
C++11, but it was never implemented in libstdc++.

libstdc++-v3/ChangeLog:

	* doc/xml/manual/intro.xml: Document LWG 581 change.
	* doc/html/manual/bugs.html: Regenerate.
	* include/bits/basic_ios.tcc: Whitespace.
	* include/bits/ostream.tcc (basic_ostream::flush()): Construct
	sentry.
	* testsuite/27_io/basic_ostream/flush/char/2.cc: Check
	additional cases.
	* testsuite/27_io/basic_ostream/flush/char/exceptions_badbit_throw.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/flush/wchar_t/2.cc: Likewise.
	* testsuite/27_io/basic_ostream/flush/wchar_t/exceptions_badbit_throw.cc:
	Likewise.
2021-06-25 18:47:39 +01:00
Jonathan Wakely
9b6c65c754 libstdc++: Fix exception handling in std::ostream seek functions
N3168 added the requirement that the [ostream.seeks] functions create a
sentry object. Nothing in the requirements of those functions says
anything about catching exceptions and setting badbit.

As well as not catching exceptions, this change results in another
observable behaviour change. Previously seeking on a stream with eofbit
set would work (as long as badbit and failbit weren't set). The
construction of a sentry causes failbit to be set when eofbit is set,
which causes the seek to fail. It is necessary to clear the eofbit
before seeking now.

libstdc++-v3/ChangeLog:

	* include/bits/ostream.tcc (sentry): Only set failbit if badbit
	is set, not if eofbit is set.
	(tellp, seekp, seekp): Create sentry object. Do not set badbit
	on exceptions.
	* testsuite/27_io/basic_ostream/seekp/char/exceptions_badbit_throw.cc:
	Adjust expected behaviour.
	* testsuite/27_io/basic_ostream/seekp/wchar_t/exceptions_badbit_throw.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/tellp/char/exceptions_badbit_throw.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/tellp/wchar_t/exceptions_badbit_throw.cc:
	Likewise.
	* testsuite/27_io/basic_ostream/seekp/char/n3168.cc: New test.
	* testsuite/27_io/basic_ostream/seekp/wchar_t/n3168.cc: New test.
	* testsuite/27_io/basic_ostream/tellp/char/n3168.cc: New test.
	* testsuite/27_io/basic_ostream/tellp/wchar_t/n3168.cc: New test.
2021-06-25 18:47:23 +01:00
Jonathan Wakely
e83a5a6b68 libstdc++: More workarounds in 17_intro/names.cc test [PR 97088]
Conditionally #undef some more names that are used in system headers.

libstdc++-v3/ChangeLog:

	PR libstdc++/97088
	* testsuite/17_intro/names.cc: Undef more names for newlib and
	also for arm-none-linux-gnueabi.
	* testsuite/experimental/names.cc: Disable PCH.
2021-06-25 18:41:24 +01:00
Matthias Kretz
74ebd1297e libstdc++: Make use of __builtin_bit_cast for simd
The __bit_cast function was a hack to achieve what __builtin_bit_cast
can do, therefore use __builtin_bit_cast if possible. However,
__builtin_bit_cast cannot be used to cast from/to fixed_size_simd, since
it isn't trivially copyable (in the language sense — in principle it
is). Therefore add __proposed::simd_bit_cast to enable the use case
required in the test framework.

Signed-off-by: Matthias Kretz <m.kretz@gsi.de>

libstdc++-v3/ChangeLog:

	* include/experimental/bits/simd.h (__bit_cast): Implement via
	__builtin_bit_cast #if available.
	(__proposed::simd_bit_cast): Add overloads for simd and
	simd_mask, which use __builtin_bit_cast (or __bit_cast #if not
	available), which return an object of the requested type with
	the same bits as the argument.
	* include/experimental/bits/simd_math.h: Use simd_bit_cast
	instead of __bit_cast to allow casts to fixed_size_simd.
	(copysign): Remove branch that was only required if __bit_cast
	cannot be constexpr.
	* testsuite/experimental/simd/tests/bits/test_values.h: Switch
	from __bit_cast to __proposed::simd_bit_cast since the former
	will not cast fixed_size objects anymore.
2021-06-25 17:32:13 +02:00
Jonathan Wakely
07ba52849f libstdc++: Fix typos and markdown errors in new simd/README.md
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* testsuite/experimental/simd/README.md: Fix typos.
2021-06-24 14:04:02 +01:00
Jonathan Wakely
17bc3848e0 libstdc++: Implement LWG 2762 for std::unique_ptr::operator*
The LWG issue proposes to add a conditional noexcept-specifier to
std::unique_ptr's dereference operator. The issue is currently in
Tentatively Ready status, but even if it isn't voted into the draft, we
can do it as a conforming extensions. This commit also adds a similar
noexcept-specifier to operator[] for the unique_ptr<T[], D> partial
specialization.

Also ensure that all dereference operators for shared_ptr are noexcept,
and adds tests for the std::optional accessors modified by the issue,
which were already noexcept in our implementation.

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

libstdc++-v3/ChangeLog:

	* include/bits/shared_ptr_base.h (__shared_ptr_access::operator[]):
	Add noexcept.
	* include/bits/unique_ptr.h (unique_ptr::operator*): Add
	conditional noexcept as per LWG 2762.
	* testsuite/20_util/shared_ptr/observers/array.cc: Check that
	dereferencing cannot throw.
	* testsuite/20_util/shared_ptr/observers/get.cc: Likewise.
	* testsuite/20_util/optional/observers/lwg2762.cc: New test.
	* testsuite/20_util/unique_ptr/lwg2762.cc: New test.
2021-06-24 14:04:02 +01:00
Patrick Palka
7da4eae3dc c++: excessive instantiation during CTAD [PR101174]
We set DECL_CONTEXT on implicitly generated deduction guides so that
their access is consistent with that of the constructor.  But this
apparently leads to excessive instantiation in some cases, ultimately
because instantiation of a deduction guide should be independent of
instantiation of the resulting class specialization, but setting the
DECL_CONTEXT of the former to the latter breaks this independence.

To fix this, this patch makes push_access_scope handle artificial
deduction guides specifically rather than setting their DECL_CONTEXT
in build_deduction_guide.  We could alternatively make the class
befriend the guide via DECL_BEFRIENDING_CLASSES, but that wouldn't
be a complete fix and would break class-deduction-access3.C below
since friendship isn't transitive.

	PR c++/101174

gcc/cp/ChangeLog:

	* pt.c (push_access_scope): For artificial deduction guides,
	set the access scope to that of the constructor.
	(pop_access_scope): Likewise.
	(build_deduction_guide): Don't set DECL_CONTEXT on the guide.

libstdc++-v3/ChangeLog:

	* testsuite/23_containers/multiset/cons/deduction.cc:
	Uncomment CTAD example that was rejected by this bug.
	* testsuite/23_containers/set/cons/deduction.cc: Likewise.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1z/class-deduction-access3.C: New test.
	* g++.dg/cpp1z/class-deduction91.C: New test.
2021-06-23 17:23:39 -04:00
Matthias Kretz
8509a50010 libstdc++: Document simd testsuite
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>

libstdc++-v3/ChangeLog:

	* testsuite/experimental/simd/README.md: New file.
2021-06-23 18:29:06 +01:00
Matthias Kretz
848bc05a98 libstdc++: Improve output verbosity options and default
For most uses --quiet was too quiet while the default was too noisy. Now
the default output, if stdout is a tty, shows the last successful test
on the same line. With --percentage it adds a percentage at the start of
the line. --percentage is not default because it requires more resources
and might not be 100% compatible to all environments.
If stdout is not a tty the default is quiet output like for dejagnu.

Additionally, argument parsing now recognizes contracted short options
which is easier to use with e.g. DRIVEROPTS=-pxk.

Signed-off-by: Matthias Kretz <m.kretz@gsi.de>

libstdc++-v3/ChangeLog:

	* testsuite/experimental/simd/driver.sh: Rewrite output
	verbosity logic. Add -p/--percentage option. Allow -v/--verbose
	to be used twice. Add -x and -o short options. Parse long
	options with = instead of separating space generically. Parce
	contracted short options. Make unrecognized options an error.
	If same-line output is active, trap on EXIT to increment the
	progress (only with --percentage), erase the line and print the
	current status.
	* testsuite/experimental/simd/generate_makefile.sh: Initialize
	helper files for progress account keeping. Update help target
	for changes to DRIVEROPTS.
2021-06-23 18:29:06 +01:00
Matthias Kretz
15f2669c9d libstdc++: Remove -fno-tree-vrp after PR98834 was resolved
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>

libstdc++-v3/ChangeLog:

	* testsuite/Makefile.am (check-simd): Remove -fno-tree-vrp flag
	and associated warning.
	* testsuite/Makefile.in: Regenerate.
2021-06-23 18:28:59 +01:00
Patrick Palka
3eecc1db4c c++: CTAD and deduction guide selection [PR86439]
During CTAD, we select the best viable deduction guide using
build_new_function_call, which performs overload resolution on the set
of candidate guides and then forms a call to the guide.  As the PR
points out, this latter step is unnecessary and occasionally incorrect
since a call to the selected guide may be ill-formed, or forming the
call may have side effects such as prematurely deducing the type of a {}.

So this patch introduces a specialized subroutine based on
build_new_function_call that stops short of building a call to the
selected function, and makes do_class_deduction use this subroutine
instead.  And since a call is no longer built, do_class_deduction
doesn't need to set tf_decltype or cp_unevaluated_operand anymore.

This change causes us to reject some container CTAD examples in the
libstdc++ testsuite due to deduction failure for {}, which AFAICT is the
correct behavior.  Previously in e.g. the first removed example

  std::map{{std::pair{1, 2.0}, {2, 3.0}, {3, 4.0}}, {}},

the type of the {} would get deduced to less<int> as a side effect of
forming a call to the chosen guide

  template<typename _Key, typename _Tp, typename _Compare = less<_Key>,
           typename _Allocator = allocator<pair<const _Key, _Tp>>>
      map(initializer_list<pair<_Key, _Tp>>,
          _Compare = _Compare(), _Allocator = _Allocator())
      -> map<_Key, _Tp, _Compare, _Allocator>;

which made later overload resolution for the constructor call
unambiguous.  Now, the type of the {} remains undeduced until
constructor overload resolution, and we complain about ambiguity
for the two equally good constructor candidates

  map(initializer_list<value_type>,
      const _Compare& = _Compare(),
      const allocator_type& = allocator_type())

  map(initializer_list<value_type>, const allocator_type&).

This patch fixes these problematic container CTAD examples by giving
the {} an appropriate concrete type.  Two of these adjusted CTAD
examples (one for std::set and one for std::multiset) end up triggering
an unrelated CTAD bug on trunk, PR101174, so these two adjusted examples
are commented out for now.

	PR c++/86439

gcc/cp/ChangeLog:

	* call.c (print_error_for_call_failure): Constify 'args' parameter.
	(perform_dguide_overload_resolution): Define.
	* cp-tree.h: (perform_dguide_overload_resolution): Declare.
	* pt.c (do_class_deduction): Use perform_dguide_overload_resolution
	instead of build_new_function_call.  Don't use tf_decltype or
	set cp_unevaluated_operand.  Remove unnecessary NULL_TREE tests.

libstdc++-v3/ChangeLog:

	* testsuite/23_containers/map/cons/deduction.cc: Replace ambiguous
	CTAD examples.
	* testsuite/23_containers/multimap/cons/deduction.cc: Likewise.
	* testsuite/23_containers/multiset/cons/deduction.cc: Likewise.
	Mention one of the replaced examples is broken due to PR101174.
	* testsuite/23_containers/set/cons/deduction.cc: Likewise.
	* testsuite/23_containers/unordered_map/cons/deduction.cc: Replace
	ambiguous CTAD examples.
	* testsuite/23_containers/unordered_multimap/cons/deduction.cc:
	Likewise.
	* testsuite/23_containers/unordered_multiset/cons/deduction.cc:
	Likewise.
	* testsuite/23_containers/unordered_set/cons/deduction.cc: Likewise.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1z/class-deduction88.C: New test.
	* g++.dg/cpp1z/class-deduction89.C: New test.
	* g++.dg/cpp1z/class-deduction90.C: New test.
2021-06-23 08:24:34 -04:00
Jonathan Wakely
75404109dc libstdc++: Avoid "__lockable" name defined as macro by newlib
libstdc++-v3/ChangeLog:

	* include/std/mutex (__detail::__try_lock_impl): Rename
	parameter to avoid clashing with newlib's __lockable macro.
	(try_lock): Add 'inline' specifier.
	* testsuite/17_intro/names.cc: Add check for __lockable.
	* testsuite/30_threads/try_lock/5.cc: Add options for pthreads.
2021-06-23 11:05:51 +01:00
Jonathan Wakely
c556596119 libstdc++: Simplify std::try_lock and std::lock further
The std::try_lock and std::lock algorithms can use iteration instead of
recursion when all lockables have the same type and can be held by an
array of unique_lock<L> objects.

By making this change to __detail::__try_lock_impl it also benefits
__detail::__lock_impl, which uses it. For std::lock we can just put the
iterative version directly in std::lock, to avoid making any call to
__detail::__lock_impl.

Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

Co-authored-by: Matthias Kretz <m.kretz@gsi.de>

libstdc++-v3/ChangeLog:

	* include/std/mutex (lock): Replace recursion with iteration
	when lockables all have the same type.
	(__detail::__try_lock_impl): Likewise. Pass lockables as
	parameters, instead of a tuple. Always lock the first one, and
	recurse for the rest.
	(__detail::__lock_impl): Adjust call to __try_lock_impl.
	(__detail::__try_to_lock): Remove.
	* testsuite/30_threads/lock/3.cc: Check that mutexes are locked.
	* testsuite/30_threads/lock/4.cc: Also test non-heterogeneous
	arguments.
	* testsuite/30_threads/unique_lock/cons/60497.cc: Also check
	std::try_lock.
	* testsuite/30_threads/try_lock/5.cc: New test.
2021-06-22 21:17:25 +01:00
Jonathan Wakely
b5a29741db libstdc++: Remove garbage collection support for C++23 [P2186R2]
This removes the non-functional garbage colection support from <memory>,
as proposed for C++23 by P2186R2.

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

libstdc++-v3/ChangeLog:

	* include/std/memory (declare_reachable, undeclare_reachable)
	(declare_no_pointers, undeclare_no_pointers, get_pointer_safety)
	(pointer_safety): Only define for C++11 to C++20 inclusive.
	* testsuite/20_util/pointer_safety/1.cc: Do not run for C++23.
2021-06-22 20:58:43 +01:00
Jonathan Wakely
6c63cb231e libstdc++: Implement LWG 3422 for std::seed_seq
This ensures that the std::seed_seq initializer-list constructor will
not be used for list-initialization unless the initializers in the list
are integers. This allows list-initialization syntax to be used with a
pair of pointers and for that to use the appropriate constructor.

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

libstdc++-v3/ChangeLog:

	* include/bits/random.h (seed_seq): Constrain initializer-list
	constructor.
	* include/bits/random.tcc (seed_seq): Add template parameter.
	* testsuite/26_numerics/random/seed_seq/cons/default.cc: Check
	for noexcept.
	* testsuite/26_numerics/random/seed_seq/cons/initlist.cc: Check
	constraints.
2021-06-22 20:58:25 +01:00
Thomas Rodgers
e02840c1a9 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.
2021-06-22 11:06:07 -07:00
Patrick Palka
69d80f0f2f libstdc++: Implement new views::split as per P2210
This implements the new views::split from P2210R2 "Superior String
Splitting".

libstdc++-v3/ChangeLog:

	* include/std/ranges (__non_propagating_cache::operator bool):
	Define for split_view::begin().
	(split_view): Define as per P2210.
	(views::__detail::__can_split_view): Define.
	(views::_Split, views::split): Define.
	* testsuite/std/ranges/adaptors/100577.cc (test01, test02):
	Test views::split.
	* testsuite/std/ranges/adaptors/split.cc: New test.
	* testsuite/std/ranges/p2325.cc (test08a): New test.
	* testsuite/std/ranges/p2367.cc (test01): Test views::split.
2021-06-20 12:47:18 -04:00
Patrick Palka
adbd2c7102 libstdc++: Implement P2210 changes to rename views::split to lazy_split
This mostly mechanical patch renames split to lazy_split throughout.

libstdc++-v3/ChangeLog:

	* include/std/ranges: Rename views::split to views::lazy_split,
	split_view to lazy_split_view, etc. throughout.
	* testsuite/std/ranges/*: Likewise.
2021-06-20 12:41:42 -04:00
Patrick Palka
3f631671f1 libstdc++: Implement P2210 changes to split_view resolving LWG 3478
This implements the part of P2210R2 "Superior String Splitting" that
resolves LWG 3478.

libstdc++-v3/ChangeLog:

	* include/std/ranges (split_view::_OuterIter::__at_end):
	Check _M_trailing_empty.
	(split_view::_OuterIter::_M_trailing_empty): Define this
	data member.
	(split_view::_OuterIter::operator++): Set _M_trailing_empty
	appropriately.
	(split_view::_OuterIter::operator==): Compare
	_M_trailing_empty.
	* testsuite/std/ranges/adaptors/100479.cc (test03): Expect two
	split parts instead of one.
	* testsuite/std/ranges/adaptors/split.cc (test11): New test.
2021-06-20 12:38:43 -04:00
Patrick Palka
cc9c94d43d 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.
2021-06-18 19:33:39 -04:00
Jonathan Wakely
0532452dcd 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.
2021-06-18 14:46:58 +01:00
Jonathan Wakely
92edc4a768 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>
2021-06-18 11:15:28 +01:00
Patrick Palka
4b4f5666b4 libstdc++: Implement P2325 changes to default-constructibility of views
This implements the wording changes of P2325R3 "Views should not be
required to be default constructible".  Changes are relatively
straightforward, besides perhaps those to __box (which now stands
for copyable-box instead of semiregular-box) and __non_propagating_cache.

For __box, this patch implements the recommended practice to also avoid
std::optional when the boxed type is nothrow_move/copy_constructible.

For __non_propagating_cache, now that it's used by split_view::_M_current,
we need to add assignment from a value of the underlying type to the
subset of the std::optional API implemented for the cache (needed by
split_view::begin()).  Hence the new __non_propagating_cache::operator=
overload.

In passing, this fixes the undesirable list-init in the constructors of
the partial specialization of __box as reported in PR100475 comment #7.

libstdc++-v3/ChangeLog:

	* include/bits/iterator_concepts.h (weakly_incrementable): Remove
	default_initializable requirement.
	* include/bits/ranges_base.h (ranges::view): Likewise.
	* include/bits/ranges_util.h (subrange): Constrain the default
	ctor.
	* include/bits/stl_iterator.h (back_insert_iterator): Remove the
	default ctor.
	(front_insert_iterator): Likewise.
	(insert_iterator): Likewise.  Remove NSDMIs.
	(common_iterator): Constrain the default ctor.
	(counted_iterator): Likewise.
	* include/bits/stream_iterator.h (ostream_iterator): Remove the
	default ctor.
	* include/std/ranges (__detail::__box::operator=): Handle
	self-assignment in the primary template.
	(__detail::__box): In the partial specialization: adjust
	constraints as per P2325.  Add specialized operator= for the
	case when the wrapped type is not copyable.  Constrain the
	default ctor.  Avoid list-initialization.
	(single_view): Constraint the default ctor.
	(iota_view): Relax semiregular constraint to copyable.
	Constrain the default ctor.
	(iota_view::_Iterator): Constraint the default ctor.
	(basic_istream_view): Remove the default ctor.  Remove NSDMIs.
	Remove redundant checks for empty _M_stream.
	(basic_istream_view::_Iterator): Likewise.
	(ref_view): Remove the default ctor.  Remove NSDMIs.
	(ref_view::_Iterator): Constrain the default ctor.
	(__detail::__non_propagating_cache::operator=): Define overload
	for assigning from a value of the underlying type.
	(filter_view): Likewise.
	(filter_view::_Iterator): Likewise.
	(transform_view): Likewise.
	(transform_view::_Iterator): Likewise.
	(take_view): Likewise.
	(take_view::_Iterator): Likewise.
	(take_while_view): Likewise.
	(take_while_view::_Iterator): Likewise.
	(drop_while_view): Likewise.
	(drop_while_view::_Iterator): Likewise.
	(join_view): Likewise.
	(split_view::_OuterIter::__current): Adjust after changing the
	type of _M_current.
	(split_view::_M_current): Wrap it in a __non_propagating_cache.
	(split_view::split_view): Constrain the default ctor.
	(common_view): Constrain the default ctor.
	(reverse_view): Likewise.
	(elements_view): Likewise.
	* include/std/span (enable_view<span<_ElementType, _Extent>>):
	Define this partial specialization to true unconditionally.
	* include/std/version (__cpp_lib_ranges): Adjust value.
	* testsuite/24_iterators/back_insert_iterator/constexpr.cc:
	Don't attempt to default construct a back_insert_iterator.
	* testsuite/24_iterators/front_insert_iterator/constexpr.cc:
	Don't attempt to default construct a front_insert_iterator.
	* testsuite/24_iterators/insert_iterator/constexpr.cc:
	Don't attempt to default construct an insert_iterator.
	* testsuite/24_iterators/ostream_iterator/requirements/constexpr.cc:
	Remove this test for default constructibility of ostream_iterator.
	* testsuite/std/ranges/97600.cc: Don't attempt to default
	construct a basic_istream_view.
	* testsuite/std/ranges/adaptors/detail/semiregular_box.cc:
	Rename to ...
	* testsuite/std/ranges/adaptors/detail/copyable_box.cc: ... this.
	(test02): Adjust now that __box is copyable-box not
	semiregular-box.
	(test03): New test.
	* testsuite/std/ranges/p2325.cc: New test.
	* testsuite/std/ranges/single_view.cc (test06): New test.
	* testsuite/std/ranges/view.cc: Adjust now that view doesn't
	require default_initializable.
2021-06-17 22:29:03 -04:00
Patrick Palka
2b87f3318c 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.
2021-06-17 09:46:07 -04:00
Patrick Palka
0f4a2fb44d 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.
2021-06-17 09:46:04 -04:00
Jonathan Wakely
b9e35ee6d6 libstdc++: Revert final/non-addressable changes to ranges CPOs
In r12-1489-g8b93548778a487f31f21e0c6afe7e0bde9711fc4 I made the
[range.access] CPO types final and non-addressable. Tim Song pointed out
this is wrong. Only the [range.iter.ops] functions should be final and
non-addressable. Revert the changes to the [range.access] objects.

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

libstdc++-v3/ChangeLog:

	* include/bits/ranges_base.h (ranges::begin, ranges::end)
	(ranges::cbegin, ranges::cend, ranges::rbeing, ranges::rend)
	(ranges::crbegin, ranges::crend, ranges::size, ranges::ssize)
	(ranges::empty, ranges::data, ranges::cdata): Remove final
	keywords and deleted operator& overloads.
	* testsuite/24_iterators/customization_points/iter_move.cc: Use
	new is_customization_point_object function.
	* testsuite/24_iterators/customization_points/iter_swap.cc:
	Likewise.
	* testsuite/std/concepts/concepts.lang/concept.swappable/swap.cc:
	Likewise.
	* testsuite/std/ranges/access/begin.cc: Likewise.
	* testsuite/std/ranges/access/cbegin.cc: Likewise.
	* testsuite/std/ranges/access/cdata.cc: Likewise.
	* testsuite/std/ranges/access/cend.cc: Likewise.
	* testsuite/std/ranges/access/crbegin.cc: Likewise.
	* testsuite/std/ranges/access/crend.cc: Likewise.
	* testsuite/std/ranges/access/data.cc: Likewise.
	* testsuite/std/ranges/access/empty.cc: Likewise.
	* testsuite/std/ranges/access/end.cc: Likewise.
	* testsuite/std/ranges/access/rbegin.cc: Likewise.
	* testsuite/std/ranges/access/rend.cc: Likewise.
	* testsuite/std/ranges/access/size.cc: Likewise.
	* testsuite/std/ranges/access/ssize.cc: Likewise.
	* testsuite/util/testsuite_iterators.h
	(is_customization_point_object): New function.
2021-06-16 14:31:04 +01:00
Jonathan Wakely
8b93548778 libstdc++: Make ranges CPOs final and not addressable
This restricts the API of the CPOs and other function objects so they
cannot be misused by deriving from them or taking their addresses.

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

libstdc++-v3/ChangeLog:

	* include/bits/ranges_base.h (ranges::begin, ranges::end)
	(ranges::cbegin, ranges::cend, ranges::rbeing, ranges::rend)
	(ranges::crbegin, ranges::crend, ranges::size, ranges::ssize)
	(ranges::empty, ranges::data, ranges::cdata): Make types final.
	Add deleted operator& overloads.
	(ranges::advance, ranges::distance, ranges::next, ranges::prev):
	Likewise.
	* testsuite/std/ranges/headers/ranges/synopsis.cc: Replace
	ill-formed & expressions with using-declarations. Add checks for
	other function objects.
2021-06-15 18:20:06 +01:00
Jonathan Wakely
9245b0e84c libstdc++: Add noexcept specifiers to some range adaptors
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/bits/ranges_util.h (view_interface): Add noexcept to
	empty, operator bool, data and size members.
	(subrange): Add noexcept to constructors.
	* include/std/ranges (single_view, ref_view): Add noexcept to
	constructors.
	(views::single, views::all): Add noexcept.
	* testsuite/std/ranges/adaptors/all.cc: Check noexcept.
	* testsuite/std/ranges/single_view.cc: Likewise.
2021-06-15 18:20:06 +01:00
Jonathan Wakely
a88fc03ba7 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.
2021-06-15 18:20:06 +01:00
Jonathan Wakely
f9598d89a9 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.
2021-06-14 23:13:16 +01:00