Patch by Maciej W. Rozycki.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/207458

From-SVN: r278316

The change approved in Belfast did not actually rename the concept from
std::default_constructible to std::default_initializable, even though
that was intended. That is expected to be done soon as a separate issue,
so I'm implementing that now too.

	* include/bits/iterator_concepts.h (weakly_incrementable): Adjust.
	* include/std/concepts (default_constructible): Rename to
	default_initializable and require default-list-initialization and
	default-initialization to be valid (LWG 3149).
	(semiregular): Adjust to new name.
	* testsuite/std/concepts/concepts.lang/concept.defaultconstructible/
	1.cc: Rename directory to concept.defaultinitializable and adjust to
	new name.
	* testsuite/std/concepts/concepts.lang/concept.defaultinitializable/
	lwg3149.cc: New test.
	* testsuite/util/testsuite_iterators.h (test_range): Adjust.

From-SVN: r278314

	* src/c++17/fs_path.cc [_GLIBCXX_FILESYSTEM_IS_WINDOWS]
	(is_disk_designator): New helper function.
	(path::_Parser::root_path()): Use is_disk_designator.
	(path::lexically_relative(const path&)): Implement resolution of
	LWG 3070.
	* testsuite/27_io/filesystem/path/generation/relative.cc: Check with
	path components that look like a root-name.

From-SVN: r278313

Add the dynamic linker name and fix a type name to use the public name
instead of the glibc internal name.

gcc/ChangeLog:

2019-11-15  Szabolcs Nagy  <szabolcs.nagy@arm.com>

	* config/m68k/linux.h (MUSL_DYNAMIC_LINKER): Define.

libgcc/ChangeLog:

2019-11-15  Szabolcs Nagy  <szabolcs.nagy@arm.com>

	* config/m68k/linux-unwind.h (struct uw_ucontext): Use sigset_t instead
	of __sigset_t.

From-SVN: r278312

This patch adds support for the C2x [[maybe_unused]] attribute, using
the same handler as for GNU __attribute__ ((unused)).

As with other such attribute support, I think turning certain warnings
into pedwarns for usage in cases where that is a constraint violation
can be addressed later as a bug fix, as can the C2x constraint for
various standard attributes that they do not appear more than once
inside a single [[]].

However, the warnings that appear in c2x-attr-maybe_unused-1.c (that
the attribute is ignored on member declarations) need to remain as
warnings not pedwarns, since C2x does permit the attribute there.  (Or
they could be silenced, on the basis that GCC doesn't have warnings
for unused struct and union members so it's completely harmless that
it's ignoring an attribute that might do something useful with another
compiler that does have such warnings.)

Bootstrapped with no regressions on x86_64-pc-linux-gnu.

gcc/c:
	* c-decl.c (std_attribute_table): Add maybe_unused.

gcc/testsuite:
	* gcc.dg/c2x-attr-maybe_unused-1.c,
	gcc.dg/c2x-attr-maybe_unused-2.c,
	gcc.dg/c2x-attr-maybe_unused-3.c: New tests.

From-SVN: r278310

ChangeLog:

2019-11-15  Kelvin Nilsen  <kelvin@gcc.gnu.org>

	* MAINTAINERS: Change my email address as maintainer.

From-SVN: r278309

microblaze-linux-musl build fails without this.

(This is a rebase of an earlier patch posted on bugzilla.)

gcc/ChangeLog:

2019-11-15  Nick Clifton  <nickc@redhat.com>
	    Szabolcs Nagy  <szabolcs.nagy@arm.com>

	PR target/65649
	* config/microblaze/microblaze.c (print_operand): Print value as long.

Co-Authored-By: Szabolcs Nagy <szabolcs.nagy@arm.com>

From-SVN: r278308

	* ipa-inline.c (edge_badness, inline_small_functions): Revert
	accidental commit.

From-SVN: r278307

Allow the registers used for the frame pointer to be used for other purposes
if the frame pointer is not being used.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.h (FIXED_REGISTERS): Unfix frame pointer.
	(CALL_USED_REGISTERS): Make frame pointer callee-saved.

From-SVN: r278306

Reduce the lower limits on the number of registers requested by non-leaf
kernels to help improve CU occupancy.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (MAX_NORMAL_SGPR_COUNT, MAX_NORMAL_VGPR_COUNT): New.
	(gcn_conditional_register_usage): Use constants in place of hard-coded
	values.
	(gcn_hsa_declare_function_name): Set lower bound for number of
	SGPRs/VGPRs in non-leaf kernels to MAX_NORMAL_SGPR_COUNT and
	MAX_NORMAL_VGPR_COUNT.

From-SVN: r278305

2019-11-15  Martin Jambor  <mjambor@suse.cz>

	* ipa-utils.h (ipa_remove_useless_jump_functions): Remove stray
	declaration.

From-SVN: r278303

Restrict the number of SGPRs and VGPRs available to non-kernel functions
to improve compute-unit occupancy with multiple threads.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (default_requested_args): New.
	(gcn_parse_amdgpu_hsa_kernel_attribute): Initialize requested args
	set with default_requested_args.
	(gcn_conditional_register_usage): Limit register usage of non-kernel
	functions.  Reassign fixed registers if a non-standard set of args is
	requested.
	* config/gcn/gcn.h (FIXED_REGISTERS): Fix registers according to ABI.

From-SVN: r278301

2019-11-15  Feng Xue  <fxue@os.amperecomputing.com>

        PR ipa/92528
        * ipa-prop.c (update_jump_functions_after_inlining): Invalidate
        aggregate jump function when inlined-to caller has no edge summary.

From-SVN: r278300

gcn_conditional_register_usage needs to be called for every function
to set the fixed registers depending on the kernel args currently
requested.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (gcn_init_cumulative_args): Call reinit_regs.

From-SVN: r278299

Rather than reimplement brace elision here, we call reshape_init and then
discard the result.  We needed to set CLASSTYPE_NON_AGGREGATE a bit more in
this patch, since outside a template it's set in check_bases_and_members.

	* pt.c (maybe_aggr_guide, collect_ctor_idx_types): New.
	(is_spec_or_derived): Split out from do_class_deduction.
	(build_deduction_guide): Handle aggregate guide.
	* class.c (finish_struct): Set CLASSTYPE_NON_AGGREGATE in a
	template.
	* cp-tree.h (CP_AGGREGATE_TYPE_P): An incomplete class is not an
	aggregate.

From-SVN: r278298

Use v1 instead of v0 when a zero-valued VGPR is needed.  This frees up
v0 for other purposes.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (gcn_expand_prologue): Remove initialization and
	prologue use of v0.
	(print_operand_address): Use v1 for zero vector offset.

From-SVN: r278297

Also add <stop_token> header to PCH and Doxygen config.

	* doc/doxygen/user.cfg.in: Add <stop_token>.
	* include/precompiled/stdc++.h: Likewise.
	* include/std/stop_token: Fix definition of std::nostopstate.
	* testsuite/30_threads/headers/stop_token/synopsis.cc: New test.
	* testsuite/30_threads/headers/thread/types_std_c++20.cc: New test.
	* testsuite/30_threads/stop_token/stop_source.cc: New test.
	* testsuite/30_threads/stop_token/stop_token.cc: Remove unnecessary
	dg-require directives. Remove I/O and inclusion of <iostream>.

From-SVN: r278296

r278235 broke conversions of vector/scalar shifts into vector/vector
shifts on targets that only provide the latter.  We need to record
whether a conversion is required in that case too.

Also, the old useless_type_conversion_p condition seemed unnecessarily
strong, since the shift amount can have a different signedness from
the shifted value and its vector type is never assumed to be identical
to vectype.  The patch therefore uses tree_nop_conversion_p instead.

2019-11-15  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	PR tree-optimization/92515
	* tree-vect-stmts.c (vectorizable_shift): Record incompatible op1
	types when converting a vector/scalar shift into a vector/vector one,
	using tree_nop_conversion_p instead of useless_type_conversion_p.
	Move the conversion code to the transform block.

From-SVN: r278295

The documentation for __RTL tests (see "(gccint) RTL Tests" info node) has the
following snippet.

```
 The parser expects the RTL body to be in the format emitted by this
dumping function:

     DEBUG_FUNCTION void
     print_rtx_function (FILE *outfile, function *fn, bool compact);

 when "compact" is true.  So you can capture RTL in the correct format
from the debugger using:

     (gdb) print_rtx_function (stderr, cfun, true);

 and copy and paste the output into the body of the C function.
```

Since r264944 print_rtx_function prints column number information, which the
__RTL function parsing does not handle.

This patch handles column number information optionally, so pre-existing __RTL
functions still work, and the above documentation quote still holds.

Note: If people would prefer to require column information I could make a
slightly neater code and update existing tests.
I guess this would be OK since the intended use for __RTL functions is in these
testcases so there is no worry about other existing code.

bootstrapped and regtested on aarch64
bootstrapped and regtested on x86_64

Ok for trunk?

Cheers,
Matthew

gcc/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* read-rtl-function.c
	(function_reader::add_fixup_source_location): Take additional
	parameter of a column.
	(function_reader::maybe_read_location): Optionally parse column
	information and pass to add_fixup_source_location.

gcc/testsuite/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* gcc.dg/rtl/aarch64/rtl-handle-column-numbers.c: New test.

From-SVN: r278294

2019-11-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/92512
	* tree-vect-loop.c (check_reduction_path): Fix operand index
	computability check.  Add check for second use in COND_EXPRs.

	* gcc.dg/torture/pr92512.c: New testcase.

From-SVN: r278293

The new tree-cfg.c checking in r278245 tripped on folds of
ALTIVEC_BUILTIN_VPERM_*, which were using gimple_convert
rather than VIEW_CONVERT_EXPR to reinterpret the contents
of a vector as a different type.

2019-11-15  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	PR target/92515
	* config/rs6000/rs6000-call.c (rs6000_gimple_fold_builtin): Use
	VIEW_CONVERT_EXPR to reinterpret vectors as different types.

From-SVN: r278292

Classify vcc_lo and vcc_hi into the VCC_CONDITIONAL_REG class,
and spill them into SGPRs if necessary.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (gcn_regno_reg_class): Return VCC_CONDITIONAL_REG
	register class for VCC_LO and VCC_HI.
	(gcn_spill_class): Use SGPR_REGS to spill registers in
	VCC_CONDITIONAL_REG.

From-SVN: r278290

2019-11-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/92324
	* tree-vect-loop.c (vect_create_epilog_for_reduction): Fix
	singedness of SLP reduction epilouge operations.  Also reduce
	the vector width for SLP reductions before doing elementwise
	operations if possible.

	* gcc.dg/vect/pr92324-4.c: New testcase.

From-SVN: r278289

2019-11-15  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/69654
	* trans-expr.c (gfc_trans_structure_assign): Move assignment to
	'cm' after treatment of C pointer types and test that the type
	has been completely built before it. Add an assert that the
	backend_decl for each component exists.

2019-11-15  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/69654
	* gfortran.dg/derived_init_6.f90: New test.

From-SVN: r278287

From-SVN: r278286

Set global epilogue_completed when skipping pro_and_epilogue pass

When compiling RTL functions marked to start at a pass after the reload
pass, `skip_pass` is used to mark the reload pass as having completed
since many patterns use the `reload_completed` variable to determine
whether to run or not.

Here we do the same for the `epilogue_completed` variable and the
pro_and_epilogue pass.

Also include a testcase that relies on the availability of a
define_split in the aarch64 backend that is conditioned on this
`epilogue_completed` variable.

regtest done on native aarch64
regtest done on native x64_86

gcc/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* passes.c (skip_pass): Set epilogue_completed if skipping the
	pro_and_epilogue pass.

gcc/testsuite/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* gcc.dg/rtl/aarch64/test-epilogue-set.c: New test.

From-SVN: r278285

2019-11-15  Andrew Stubbs  <ams@codesourcery.com>

	libgomp/
	* testsuite/libgomp.c/target-print-1.c: New file.
	* testsuite/libgomp.fortran/target-print-1.f90: New file.
	* testsuite/libgomp.oacc-c/print-1.c: New file.
	* testsuite/libgomp.oacc-fortran/print-1.f90: New file.

From-SVN: r278284

Hi there,

When compiling an __RTL function that has an invalid "startwith" pass we
currently don't run the dfinish cleanup pass. This means we ICE on the next
function.

This change ensures that all state is cleaned up for the next function
to run correctly.

As an example, before this change the following code would ICE when compiling
the function `foo2` because the "peephole2" pass is not run at optimisation
level -O0.

When compiled with
./aarch64-none-linux-gnu-gcc -O0 -S missed-pass-error.c -o test.s

```
int __RTL (startwith ("peephole2")) badfoo ()
{
(function "badfoo"
  (insn-chain
    (block 2
      (edge-from entry (flags "FALLTHRU"))
      (cnote 3 [bb 2] NOTE_INSN_BASIC_BLOCK)
      (cinsn 101 (set (reg:DI x19) (reg:DI x0)))
      (cinsn 10 (use (reg/i:SI x19)))
      (edge-to exit (flags "FALLTHRU"))
    ) ;; block 2
  ) ;; insn-chain
) ;; function "foo2"
}

int __RTL (startwith ("final")) foo2 ()
{
(function "foo2"
  (insn-chain
    (block 2
      (edge-from entry (flags "FALLTHRU"))
      (cnote 3 [bb 2] NOTE_INSN_BASIC_BLOCK)
      (cinsn 101 (set (reg:DI x19) (reg:DI x0)))
      (cinsn 10 (use (reg/i:SI x19)))
      (edge-to exit (flags "FALLTHRU"))
    ) ;; block 2
  ) ;; insn-chain
) ;; function "foo2"
}
```

Now it silently ignores the __RTL function and successfully compiles foo2.

regtest done on aarch64
regtest done on x86_64

OK for trunk?

gcc/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* passes.c (should_skip_pass_p): Always run "dfinish".

gcc/testsuite/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* gcc.dg/rtl/aarch64/missed-pass-error.c: New test.

From-SVN: r278283

2019-11-15  Richard Biener  <rguenther@suse.de>

	* ipa-inline.c (inline_small_functions): Move assignment
	to next before call destroying edge.

From-SVN: r278282

2019-11-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/92039
	PR tree-optimization/91975
	* tree-ssa-loop-ivcanon.c (constant_after_peeling): Revert
	previous change, treat invariants consistently as non-constant.
	(tree_estimate_loop_size): Ternary ops with just the first op
	constant are not optimized away.

	* gcc.dg/tree-ssa/cunroll-2.c: Revert to state previous to
	unroller adjustment.
	* g++.dg/tree-ssa/ivopts-3.C: Likewise.

From-SVN: r278281

	* gimplify.c (gimplify_call_expr): Don't call
	omp_resolve_declare_variant after gimplification.
	* omp-general.c (omp_context_selector_matches): For isa that might
	match in some other function, defer if in declare simd function.
	(omp_context_compute_score): Don't look for " score" in construct
	trait set.  Set *score to -1 if it can't ever match.
	(omp_resolve_declare_variant): If any variants need to be deferred,
	don't punt immediately, but compute scores of all variants and if
	ther eis a score winner that doesn't need to be deferred, return that.

	* c-c++-common/gomp/declare-variant-13.c: New test.

From-SVN: r278280

	PR testsuite/92520
	* gcc.dg/ipa/inline-9.c: Fix template.

From-SVN: r278279

gcc/ChangeLog:

	2019-11-15  Luo Xiong Hu  <luoxhu@linux.ibm.com>

	* ipa-comdats.c: Fix comments typo.
	* ipa-profile.c: Fix comments typo.
	* tree-profile.c (gimple_gen_ic_profiler): Use the new variable
	__gcov_indirect_call.counters and __gcov_indirect_call.callee.
	(gimple_gen_ic_func_profiler): Likewise.
	(pass_ipa_tree_profile::gate): Fix comments typo.

From-SVN: r278278

next is initialized only in the loop before, it is never updated
in it's own loop.

gcc/ChangeLog:

	2019-11-15  Xiong Hu Luo  <luoxhu@linux.ibm.com>

	* ipa-inline.c (inline_small_functions): Update iterator of next.

From-SVN: r278277

    
    When the compiler writes an inlinable function to the export data,
    parameter names are written out (in Export::write_name) using the
    Gogo::message_name as opposed to a raw/encoded name. This means that
    sink parameters (those named "_") get created with the name "_"
    instead of "._" (the name created by the lexer/parser). This confuses
    Gogo::is_sink_name, which looks for the latter sequence and not just
    "_". This can cause issues later on if an inlinable function is
    imported and fed through the rest of the compiler (things that are
    sinks are no recognized as such). To fix these issues, change
    Gogo::is_sink_name to return true for either variants ("_" or "._").
    
    Fixes golang/go#35586.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/207259

From-SVN: r278275

        * include/Makefile.am: Add <stop_token> header.
        * include/Makefile.in: Regenerate.
        * include/std/condition_variable: Add overloads for stop_token support
        to condition_variable_any.
        * include/std/stop_token: New file.
        * include/std/thread: Add jthread type.
        * include/std/version (__cpp_lib_jthread): New value.
        * testsuite/30_threads/condition_variable_any/stop_token/1.cc: New test.
        * testsuite/30_threads/condition_variable_any/stop_token/2.cc: New test.
        * testsuite/30_threads/condition_variable_any/stop_token/wait_on.cc: New test.
        * testsuite/30_threads/jthread/1.cc: New test.
        * testsuite/30_threads/jthread/2.cc: New test.
        * testsuite/30_threads/jthread/jthread.cc: New test.
        * testsuite/30_threads/stop_token/1.cc: New test.
        * testsuite/30_threads/stop_token/2.cc: New test.
        * testsuite/30_threads/stop_token/stop_token.cc: New test.

From-SVN: r278274

When adding C2x attribute support, some [[fallthrough]] support
appeared as a side-effect because of code for that attribute going
through separate paths from the normal attribute handling.

However, going through those paths without the normal attribute
handlers meant that certain checks, such as for the invalid usage
[[fallthrough()]], did not operate.  This patch improves checks by
adding this attribute to the standard attribute table, so that the
parser knows it expects no arguments, along with adding an explicit
check for "[[fallthrough]];" attribute-declarations at top level.  As
with other attributes, there are still cases where warnings should be
pedwarns because C2x constraints are violated, but this patch improves
the attribute handling.

Bootstrapped with no regressions on x86_64-pc-linux-gnu.

gcc/c:
	* c-decl.c (std_attribute_table): Add fallthrough.
	* c-parser.c (c_parser_declaration_or_fndef): Diagnose fallthrough
	attribute at top level.

gcc/c-family:
	* c-attribs.c (handle_fallthrough_attribute): Remove static.
	* c-common.h (handle_fallthrough_attribute): Declare.

gcc/testsuite:
	* gcc.dg/c2x-attr-fallthrough-2.c,
	gcc.dg/c2x-attr-fallthrough-3.c: New tests.

From-SVN: r278273

From-SVN: r278272

2019-11-14  Edward Smith-Rowland  <3dw4rd@verizon.net>

	Implement the <array> part of C++20 p1032 Misc constexpr bits.
	* include/std/array (fill, swap): Make constexpr.
	* testsuite/23_containers/array/requirements/constexpr_fill.cc: New.
	* testsuite/23_containers/array/requirements/constexpr_swap.cc: New.

From-SVN: r278269

This patch adds support for the C2x [[deprecated]] attribute.  All the
actual logic for generating warnings can be identical to the GNU
__attribute__ ((deprecated)), as can the attribute handler, so this is
just a matter of wiring things up appropriately and adding the checks
specified in the standard.  Unlike for C++, this patch gives
"deprecated" an entry in a table of standard attributes rather than
remapping it internally to the GNU attribute, as that seems a cleaner
approach to me.

Specifically, the only form of arguments to the attribute permitted in
the standard is (string-literal); empty parentheses are not permitted
in the case of no arguments, and a string literal (which includes
concatenated adjacent string literals, because concatenation is an
earlier phase of translation) cannot have further redundant
parentheses around it.  For the case of empty parentheses, this patch
makes the C parser disallow them for all known attributes using the
[[]] syntax, as done for C++.  For string literals (where the C++
front end is missing the check to avoid redundant parentheses, 92521
filed for that issue), a special case is inserted in the C parser.

A known issue that I think can be addressed later as a bug fix is that
the warnings for the attribute being ignored in certain cases
(attribute declarations, statements, most uses on types) ought to be
pedwarns, as those usages are constraint violations.

Bad handling of wide string literals with this attribute is also a
pre-existing bug (91182 - although that's filed as a C++ bug, the code
in question is language-independent, in tree.c).

Bootstrapped with no regressions on x86_64-pc-linux-gnu.

gcc/c:
	* c-decl.c (std_attribute_table): New.
	(c_init_decl_processing): Register attributes from
	std_attribute_table.
	* c-parser.c (c_parser_attribute_arguments): Add arguments
	require_string and allow_empty_args.  All callers changed.
	(c_parser_std_attribute): Set require_string argument for
	"deprecated" attribute.

gcc/c-family:
	* c-attribs.c (handle_deprecated_attribute): Remove static.
	* c-common.h (handle_deprecated_attribute): Declare.

gcc/testsuite:
	* gcc.dg/c2x-attr-deprecated-1.c, gcc.dg/c2x-attr-deprecated-2.c,
	gcc.dg/c2x-attr-deprecated-3.c: New tests.

From-SVN: r278268