The stack frame for the function in the testcase consisted of two
SVE save slots.  Both saves had been shrink-wrapped, but for different
blocks, meaning that the stack allocation and deallocation were
separate from the saves themselves.  Before emitting the deallocation,
we tried to attach a REG_CFA_DEF_CFA note to the preceding instruction,
to redefine the CFA in terms of the stack pointer.  But in this case
there was no preceding instruction.

This in practice only happens for SVE because:

(a) We don't try to shrink-wrap wb_candidate* registers even when
    we've decided to treat them as normal saves and restores.
    I have a fix for that.

(b) Even with (a) fixed, we're (almost?) guaranteed to emit
    a stack tie for frames that are 64k or larger, so we end
    up hanging the REG_CFA_DEF_CFA note on that instead.

We should only need to redefine the CFA if it was previously
defined in terms of the frame pointer.  In other cases the CFA
should already be defined in terms of the stack pointer,
so redefining it is unnecessary but usually harmless.

2020-05-28  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	PR testsuite/95361
	* config/aarch64/aarch64.c (aarch64_expand_epilogue): Only
	redefine the CFA if we have CFI operations.

gcc/testsuite/
	PR testsuite/95361
	* gcc.target/aarch64/sve/pr95361.c: New test.

Based on a patch in the comments of the PR. That patch fixed this
problem but caused the test cases for PR93484 to fail. It has been
changed to reduce initialisation expressions if the expression is
not EXPR_VARIABLE and not EXPR_CONSTANT.

2020-05-28  Steven G. Kargl  <kargl@gcc.gnu.org>
	    Mark Eggleston  <markeggleston@gcc.gnu.org>

gcc/fortran/

	PR fortran/94397
	* match.c (gfc_match_type_spec): New variable ok initialised
	to true. Set ok with the return value of gfc_reduce_init_expr
	called only if the expression is not EXPR_CONSTANT and is not
	EXPR_VARIABLE. Add !ok to the check for type not being integer
	or the rank being greater than zero.

2020-05-28  Mark Eggleston  <markeggleston@gcc.gnu.org>

gcc/testsuite/

	PR fortran/94397
	* gfortran.dg/pr94397.F90: New test.

(cherry picked from commit 3ea6977d0f1813d982743a09660eec1760e981ec)

PFPNACC insn is incorrectly modelled to perform addition and subtraction
of two operands, but in reality it performs horizontal addition and
subtraction:

Instruction: PFPNACC dest,src

Description:
dest[31:0] <- dest[31:0] - dest[63:32];
dest[63:32] <- src[31:0] + src[63:32];

2020-05-28  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:
	* config/i386/mmx.md (mmx_haddsubv2sf3): Correct
	RTL template to model horizontal subtraction and addition.

2020-05-28  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:
	PR target/95355
	* config/i386/sse.md
	(<mask_codefor>avx512f_<code>v16qiv16si2<mask_name>):
	Remove %q operand modifier from insn template.
	(avx512f_<code>v8hiv8di2<mask_name>): Ditto.

gcc/testsuite/ChangeLog:
	PR target/95355
	* gcc.target/i386/pr95355.c: New test.

The patch fixes various issues spotted by check-params-in-docs.py
script. I'm going to install the patch.

gcc/ChangeLog:

	PR web/95380
	* doc/invoke.texi: Add missing params, remove max-once-peeled-insns and
	rename ipcp-unit-growth to ipa-cp-unit-growth.

(cherry picked from commit 48e872db11b27604f4993f9be8f67f40b1a40468)

A function may contain an assigned goto.  If the the return variable
is an integer a statement can be assigned to it.  Prior to this fix
this resulted in an ICE.

2020-05-28  Tobias Burnus  <tobias@codesourcery.com>

gcc/fortran/

	PR fortran/50392
	* trans-decl.c (gfc_get_symbol_decl): Remove unnecessary block
	delimiters.  Add auxiliary variables if a label is assigned to
	a return variable. (gfc_gat_fake_result): If the symbol has an
	assign attribute set declaration from the symbol's backend
	declaration.

2020-05-28  Mark Eggleston  <markeggleston@gnu.gcc.org>

gcc/testsuite/

	PR fortran/50392
	* gfortran.dg/pr50392.f: New test.

(cherry picked from commit a7fd43c38f7469a3ef5ee30e889d60e1376d4dfc)

This patch fixes the definition of common_iterator::operator-> when the
underlying iterator's operator* returns a non-reference.

The first problem is that the class __detail::_Common_iter_proxy is used
unqualified.  Fixing that revealed another problem: the class's template
friend declaration of common_iterator doesn't match up with the
definition of common_iterator, because the friend declaration isn't
constrained.

If we try to make the friend declaration match up by adding constraints,
we run into frontend bug PR93467.  So we currently can't correctly
express this friend relation between __detail::_Common_iter_proxy and
common_iterator.

As a workaround to this frontend bug, this patch moves the definition of
_Common_iter_proxy into the class template of common_iterator so that we
could instead express the friend relation via the injected-class-name.

(This bug was found when attempting to use views::common to work around
the compile failure with the testcase in PR95322.)

libstdc++-v3/ChangeLog:

	PR libstdc++/95322
	* include/bits/stl_iterator.h (__detail::_Common_iter_proxy):
	Remove and instead define it ...
	(common_iterator::_Proxy): ... here.
	(common_iterator::operator->): Use it.
	* testsuite/24_iterators/common_iterator/2.cc: New test.
	* testsuite/std/ranges/adaptors/95322.cc: New test.

(cherry picked from commit 3bf5e7657b752cc2352778e8c20ac9cdddca4f93)

Referencing a unit in a WAIT statement that has not been opened before
resulted in a NULL pointer dereference.  Check for this condition.

2020-05-26  Harald Anlauf  <anlauf@gmx.de>

libgfortran/
	PR libfortran/95104
	* io/transfer.c (st_wait_async): Do not dereference NULL pointer.

gcc/testsuite/
	PR libfortran/95104
	* gfortran.dg/pr95104.f90: New test.

Co-Authored-By: Steven G. Kargl  <kargl@gcc.gnu.org>
(cherry picked from commit 56f03cd12be26828788a27f6f3c250041a958e45)

Here, when considering the two 'insert' overloads, we look for aggregate
conversions from the same initializer-list to B<3> or
initializer_list<B<3>>.  But since my fix for reshape_init overhead on the
PR14179 testcase we reshaped the initializer-list directly, leading to an
error when we then tried to reshape it differently for the second overload.

gcc/cp/ChangeLog:

	PR c++/95319
	* decl.c (reshape_init_array_1): Don't reuse in overload context.

gcc/testsuite/ChangeLog:

	PR c++/95319
	* g++.dg/cpp0x/initlist-array12.C: New test.

(cherry picked from commit 6efa97ea1d2fe6df1fbb9df78faaa2248a8618d7)

contrib/ChangeLog:

	* git-backport.py: New file.

In C++20, if there is no viable operator< available, lhs < rhs gets
rewritten to (lhs <=> rhs) < 0, where operator< for the comparison
categories is intended to accept literal 0 on the RHS but not other
integers.  We don't want this to produce a warning from
-Wzero-as-null-pointer-constant.

gcc/cp/ChangeLog:

	* call.c (build_new_op_1): Suppress
	warn_zero_as_null_pointer_constant across comparison of <=> result
	to 0.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp2a/spaceship-synth2.C: Add
	-Wzero-as-null-pointer-constant.

(cherry picked from commit 6c66c692043d680a5efcd9616b94f9629c417038)

Another case that breaks with my fix for PR90750: we shouldn't move type
attributes in TYPENAME context either, as there's no decl for them to move
to.

gcc/cp/ChangeLog:

	PR c++/95222
	* decl.c (grokdeclarator): Don't shift attributes in TYPENAME
	context.

gcc/testsuite/ChangeLog:

	PR c++/95222
	* g++.dg/ext/tmplattr10.C: New test.

(cherry picked from commit 7e7d9fcff56385812764cba63e1ebf6f4c6c0320)

gcc/fortran/ChangeLog:

2020-05-23  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR libfortran/95191
	* libgfortran.h (libgfortran_error_codes): Add
	LIBERROR_BAD_WAIT_ID.

libgfortran/ChangeLog:

2020-05-23  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR libfortran/95191
	* io/async.c (async_wait_id): Generate error if ID is higher
	than the highest current ID.
	* runtime/error.c (translate_error): Handle LIBERROR_BAD_WAIT_ID.

libgomp/ChangeLog:

2020-05-23  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR libfortran/95191
	* testsuite/libgomp.fortran/async_io_9.f90: New test.

(cherry picked from commit 8df7ee67f6fdc780e9453f2baa8d1bf62c000761)

Vxworks 7's malloc, like Solaris', only ensures 8-byte alignment of
returned pointers on 32-bit x86, though GCC's stddef.h defines
max_align_t with 16-byte alignment for __float128.  This patch enables
on x86-vxworks the same memory_resource workaround used for x86-solaris.

The testsuite also had a workaround, defining BAD_MAX_ALIGN_T and
xfailing the test; extend those to x86-vxworks as well, and remove the
check for char-aligned requested allocation to be aligned like
max_align_t.  With that change, the test passes on x86-vxworks; I'm
guessing that's the same reason for the test not to pass on
x86-solaris (and on x86_64-solaris -m32), so with the fix, I'm
tentatively removing the xfail.


for libstdc++-v3/ChangeLog

	PR libstdc++/77691
	* include/experimental/memory_resource
	(__resource_adaptor_imp::do_allocate): Handle max_align_t on
	x86-vxworks as on x86-solaris.
	(__resource_adaptor_imp::do_deallocate): Likewise.
	* testsuite/experimental/memory_resource/new_delete_resource.cc:
	Drop xfail.
	(BAD_MAX_ALIGN_T): Define on x86-vxworks as on x86-solaris.
	(test03): Drop max-align test for char-aligned alloc.

(cherry picked from commit 883246530f1bb10d854f455e1c3d55b93675690a)

gcc/testsuite/ChangeLog
2020-05-12  Jason Merrill  <jason@redhat.com>

	* lib/target-supports.exp (check_effective_target_c++20_only)
	(check_effective_target_c++20): New.

This is the same issue as PR86429, just in potential_constant_expression_1
rather than cxx_eval_constant_expression.  As in that case, when we're
trying to evaluate a constant expression within a lambda, we don't have a
constant closure object to refer to, but we can try to refer directly to the
captured variable.

gcc/cp/ChangeLog
2020-05-05  Jason Merrill  <jason@redhat.com>

	PR c++/90212
	* constexpr.c (potential_constant_expression_1): In a lambda
	function, consider a captured variable directly.

For default member initializers in templates it's important to push into the
right context during get_nsdmi.  But for a local class that's not possible,
and trying leaves the function context we need to be in, so don't try.

gcc/cp/ChangeLog
2020-05-01  Jason Merrill  <jason@redhat.com>

	PR c++/90479
	* init.c (get_nsdmi): Don't push_to_top_level for a local class.

cp_finish_decl avoids setting TREE_READONLY on TREE_STATIC variables that
have non-constant construction or destruction, but -fmerge-all-constants was
converting an automatic variable to static while leaving TREE_READONLY set.

Fixed by clearing the flag in cp_finish_decl in the presence of
-fmerge-all-constants.

gcc/cp/ChangeLog
2020-05-01  Jason Merrill  <jason@redhat.com>

	PR c++/91529
	* decl.c (cp_finish_decl): Also clear TREE_READONLY if
	-fmerge-all-constants.

Within the generic lambda the VLA capture proxy VAR_DECL has DECL_VALUE_EXPR
which is a NOP_EXPR to the VLA type of the proxy.  The problem here was that
when instantiating we were tsubsting that type twice, once for the type of
the DECL and once for the type of the NOP_EXPR, and getting two
different (though equivalent) types.  Then gimplify_type_sizes fixed up the
type of the DECL, but that didn't affect the type of the NOP_EXPR, leading
to sadness.

Fixed by directly reusing the type from the DECL.

gcc/cp/ChangeLog
2020-05-01  Jason Merrill  <jason@redhat.com>

	PR c++/93822
	* pt.c (tsubst_decl): Make sure DECL_VALUE_EXPR continues to have
	the same type as the variable.

2020-05-24  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:
	PR target/95255
	* config/i386/i386.md (<rounding_insn><mode>2): Do not try to
	expand non-sse4 ROUND_ROUNDEVEN rounding via SSE support routines.

gcc/testsuite/ChangeLog:
	PR target/95255
	* gcc.target/i386/pr95255.c: New test.

Another case where we need a linker-visible symbol in order
to preserve the ld64 atom model.  If these symbols are emitted
as 'local' the linker cannot see that they are separate from any
global weak entry that precedes them.  This will cause the linker
to complain that there is (apparently) direct access to such a
weak global.

This is a short-term fix for the problem - ideally we need a more
generic handling for all the relevant cases.

	Backport 804254edb48f87d726a1bc9e95af04076c030e35

gcc/ChangeLog:

	* config/darwin.h (ASM_GENERATE_INTERNAL_LABEL):
	Make ubsan_{data,type},ASAN linker-visible.

Add -mavx512vpopcntdq for -march=native if AVX512VPOPCNTDQ is available.

	PR target/95258
	* config/i386/driver-i386.c (host_detect_local_cpu): Detect
	AVX512VPOPCNTDQ.

(cherry picked from commit 808b611bfb4b05703ea174e50874c711dca44c98)

This is a case where the standard contains conflicting information.
after discussion between implementators, the accepted intent is of
[class.copy.elision].  This amends the handling of co_return statements
to follow that.

	Backport 5ef067eb14d40337507077a8a1265a04daa8ebc1 and f898793b4545483adaf62c5efbc78cee518884e6

gcc/cp/ChangeLog:

	* coroutines.cc (finish_co_return_stmt): Implement rules
	from [class.copy.elision] /3.

gcc/testsuite/ChangeLog:

	* g++.dg/coroutines/co-return-syntax-10-movable.C: New test.

These functions were originally static members of the path class, but
the 'static' specifiers were not removed when they were moved to
namespace scope. This causes ODR violations when the functions are
called from functions defined in the header. Change them to 'inline'
instead.

Backport from mainline
2020-05-23  Jonathan Wakely  <jwakely@redhat.com>

	* include/bits/fs_path.h (__detail::_S_range_begin)
	(__detail::_S_range_end): Remove unintentional static specifiers.
	* include/experimental/bits/fs_path.h (__detail::_S_range_begin)
	(__detail::_S_range_end): Likewise.

The body of this function isn't just a return statement, so it can't be
constexpr until C++14.

Backport from mainline
2020-05-23  Jonathan Wakely  <jwakely@redhat.com>

	PR libstdc++/95289
	* include/debug/helper_functions.h (__get_distance): Only declare
	as a constexpr function for C++14 and up.
	* testsuite/25_algorithms/copy/debug/95289.cc: New test.

2020-05-14  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR libfortran/95119
	* io/close.c (close_status): Add CLOSE_INVALID.
	(st_close): Return early on invalid STATUS parameter.

2020-05-14  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR libfortran/95119
	* testsuite/libgomp.fortran/close_errors_1.f90: New test.

(cherry picked from commit cdc34b505796327b3eee9e97bc5f27ba71fd9e7a)
(cherry picked from commit d975519ad1066ed0397714c91aafadadb52a63dd)

This documents new GCC 10 behavior on diagnostic options and -flto.

2020-05-22  Richard Biener  <rguenther@suse.de>

	PR lto/95190
	* doc/invoke.texi (flto): Document behavior of diagnostic
	options.

(cherry picked from commit ab7eca92926fdc1da880120c116a1832fce56a29)

2020-05-21  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:
	PR target/95169
	* config/i386/i386-expand.c (ix86_expand_int_movcc):
	 Avoid reversing a non-trapping comparison to a trapping one.

gcc/testsuite/ChangeLog:
	PR target/95169
	* gcc.target/i386/pr95169.c: New test.

	* common/config/aarch64/aarch64-common.c (aarch64_handle_option):
	Handle OPT_moutline_atomics.
	* config/aarch64/aarch64.c: Add outline-atomics to
	aarch64_attributes.

	* doc/extend.texi: Document the newly added target attribute.

	* gcc.target/aarch64/target_attr_20.c: New test.
	* gcc.target/aarch64/target_attr_21.c: New test.

(cherry picked from commit 9e02b45ffc60e0078bde3c56a14f00c54b7f8039)

Move FEATURE_AVX512VP2INTERSECT after FEATURE_AVX512BF16 to avoid
changing libgcc ABI.

gcc/

	PR target/95212
	* config/i386/i386-builtins.c (processor_features): Move
	F_AVX512VP2INTERSECT after F_AVX512BF16.
	(isa_names_table): Likewise.

libgcc/

	PR target/95212
	* config/i386/cpuinfo.h (processor_features): Move
	FEATURE_AVX512VP2INTERSECT after FEATURE_AVX512BF16.

(cherry picked from commit 5855bdfa06fb25c0880af89cb2bfdcdf342beac2)

Also add some missing member functions, nodiscard attributes, and
noexcept-specifiers.

Backport from mainline
2020-05-21  Jonathan Wakely  <jwakely@redhat.com>

	* include/experimental/executor (use_future_t::use_future_t()): Fix
	incorrect noexcept-specifier.
	* include/experimental/internet (basic_resolver_results): Adjust
	whitespace.
	* include/experimental/socket (__basic_socket_impl::release): Add
	member function.
	(basic_socket(io_context&, const endpoint_type&)): Fix argument to
	target constructor.
	(basic_socket::release(), basic_socket::release(error_code&)): Add
	missing member functions.
	(basic_socket::is_open()): Add nodiscard attribute.
	(basic_socket::close(error_code&)): Pass argument to base function.
	(basic_socket_acceptor::release())
	(basic_socket_acceptor::release(error_code&)): Add missing member
	functions.
	(basic_socket_acceptor::is_open()): Add nodiscard attribute.
	(basic_socket_streambuf::error()): Add noexcept.
	(basic_socket_iostream::error()): Likewise.
	* testsuite/experimental/net/socket/basic_socket.cc: New test.

Checking whether a filesystem::path constructor argument is an iterator
requires instantiating std::iterator_traits. In C++20 that checks for
satisfaction of std::iterator_traits constraints, which checks if the
type is copyable, which can end up recursing back to the path
constructor. The fix in LWG 3420 is to reorder the cpp17-iterator
concept's constraints to check if the type looks vaguely like an
iterator before checking copyable. That avoids the recursion for types
which definitely aren't iterators, but isn't foolproof.

Backport from mainline
2020-05-21  Jonathan Wakely  <jwakely@redhat.com>

	PR libstdc++/93983
	* include/bits/iterator_concepts.h (__detail::__cpp17_iterator):
	Reorder constraints to avoid recursion when constructors use
	iterator_traits (LWG 3420).
	* testsuite/24_iterators/customization_points/lwg3420.cc: New test.

Update VPCLMULQDQ check to support processors with AVX version of
VPCLMULQDQ.

	Backport from master
	PR target/91695
	* config/i386/cpuinfo.c (get_available_features): Fix VPCLMULQDQ
	check.

(cherry picked from commit 1e46a443f25d26816536c0c480211714b123a1d5)