After building some larger codes using opaque types and some c++ codes
using opaque types it became clear I needed to go through and look for
places where opaque types and modes needed to be handled. A whole pile
of one-liners.

gcc/
	* typeclass.h: Add opaque_type_class.
	* builtins.c (type_to_class): Identify opaque type class.
	* dwarf2out.c (is_base_type): Handle opaque types.
	(gen_type_die_with_usage): Handle opaque types.
	* expr.c (count_type_elements): Opaque types should
	never have initializers.
	* ipa-devirt.c (odr_types_equivalent_p): No type-specific handling
	for opaque types is needed as it eventually checks the underlying
	mode which is what is important.
	* tree-streamer.c (record_common_node): Handle opaque types.
	* tree.c (type_contains_placeholder_1): Handle opaque types.
	(type_cache_hasher::equal): No additional comparison needed for
	opaque types.
gcc/c-family
	* c-pretty-print.c (c_pretty_printer::simple_type_specifier):
	Treat opaque types like other types.
	(c_pretty_printer::direct_abstract_declarator): Opaque types are
	supported types.
gcc/c
	* c-aux-info.c (gen_type): Support opaque types.
gcc/cp
	* error.c (dump_type): Handle opaque types.
	(dump_type_prefix): Handle opaque types.
	(dump_type_suffix): Handle opaque types.
	(dump_expr): Handle opaque types.
	* pt.c (tsubst): Allow opaque types in templates.
	(unify): Allow opaque types in templates.
	* typeck.c (structural_comptypes): Handle comparison
	of opaque types.

On macOS / Darwin, the environ variable can be used directly in the
code of an executable, but cannot be used in the code of a shared
library (i.e. libgfortran.dylib), in this case.

In such cases, the  function _NSGetEnviron should be called to get
the address of 'environ'.

libgfortran/ChangeLog:

	* intrinsics/execute_command_line.c (environ): Use
	_NSGetEnviron to get the environment pointer on Darwin.

The sanitizer is supported for at least x86_64 and Darwin20.

libsanitizer/ChangeLog:

	* configure.tgt: Allow x86_64 Darwin2x.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/272146

Since the test is compiled with -fno-builtin, include math.h to allow for
implementations (like the PowerPC) that have multiple versions of long double
that are selectable by switch.  Math.h could possibly switch what function
nextafterl points to.

gcc/testsuite/
2020-11-17  Michael Meissner  <meissner@linux.ibm.com>

	* gcc.dg/nextafter-2.c: Include math.h.

This patch adds support for mapping the scalar_cmp_exp_qp_* built-in functions
to handle arguments that are either TFmode or KFmode, depending on whether long
double uses the IEEE 128-bit representation (TFmode) or the IBM 128-bit
representation (KFmode).  This shows up in the float128-cmp2-runnable.c test
when long double uses the IEEE 128-bit representation.

gcc/
2020-11-20  Michael Meissner  <meissner@linux.ibm.com>

	* config/rs6000/rs6000-call.c (rs6000_expand_builtin): Add missing
	XSCMP* cases for IEEE 128-bit long double.

Add support for -
  * atomic_flag::wait/notify_one/notify_all
  * atomic::wait/notify_one/notify_all
  * counting_semaphore
  * binary_semaphore
  * latch

libstdc++-v3/ChangeLog:

	* include/Makefile.am (bits_headers): Add new header.
	* include/Makefile.in: Regenerate.
	* include/bits/atomic_base.h (__atomic_flag::wait): Define.
	(__atomic_flag::notify_one): Likewise.
	(__atomic_flag::notify_all): Likewise.
	(__atomic_base<_Itp>::wait): Likewise.
	(__atomic_base<_Itp>::notify_one): Likewise.
	(__atomic_base<_Itp>::notify_all): Likewise.
	(__atomic_base<_Ptp*>::wait): Likewise.
	(__atomic_base<_Ptp*>::notify_one): Likewise.
	(__atomic_base<_Ptp*>::notify_all): Likewise.
	(__atomic_impl::wait): Likewise.
	(__atomic_impl::notify_one): Likewise.
	(__atomic_impl::notify_all): Likewise.
	(__atomic_float<_Fp>::wait): Likewise.
	(__atomic_float<_Fp>::notify_one): Likewise.
	(__atomic_float<_Fp>::notify_all): Likewise.
	(__atomic_ref<_Tp>::wait): Likewise.
	(__atomic_ref<_Tp>::notify_one): Likewise.
	(__atomic_ref<_Tp>::notify_all): Likewise.
	(atomic_wait<_Tp>): Likewise.
	(atomic_wait_explicit<_Tp>): Likewise.
	(atomic_notify_one<_Tp>): Likewise.
	(atomic_notify_all<_Tp>): Likewise.
	* include/bits/atomic_wait.h: New file.
	* include/bits/atomic_timed_wait.h: New file.
	* include/bits/semaphore_base.h: New file.
	* include/std/atomic (atomic<bool>::wait): Define.
	(atomic<bool>::wait_one): Likewise.
	(atomic<bool>::wait_all): Likewise.
	(atomic<_Tp>::wait): Likewise.
	(atomic<_Tp>::wait_one): Likewise.
	(atomic<_Tp>::wait_all): Likewise.
	(atomic<_Tp*>::wait): Likewise.
	(atomic<_Tp*>::wait_one): Likewise.
	(atomic<_Tp*>::wait_all): Likewise.
	* include/std/latch: New file.
	* include/std/semaphore: New file.
	* include/std/version: Add __cpp_lib_semaphore and
	__cpp_lib_latch defines.
	* testsuite/29_atomics/atomic/wait_notify/bool.cc: New test.
	* testsuite/29_atomics/atomic/wait_notify/pointers.cc: Likewise.
	* testsuite/29_atomics/atomic/wait_notify/generic.cc: Liekwise.
	* testsuite/29_atomics/atomic_flag/wait_notify/1.cc: Likewise.
	* testsuite/29_atomics/atomic_float/wait_notify.cc: Likewise.
	* testsuite/29_atomics/atomic_integral/wait_notify.cc: Likewise.
	* testsuite/29_atomics/atomic_ref/wait_notify.cc: Likewise.
	* testsuite/30_threads/semaphore/1.cc: New test.
	* testsuite/30_threads/semaphore/2.cc: Likewise.
	* testsuite/30_threads/semaphore/least_max_value_neg.cc: Likewise.
	* testsuite/30_threads/semaphore/try_acquire.cc: Likewise.
	* testsuite/30_threads/semaphore/try_acquire_for.cc: Likewise.
	* testsuite/30_threads/semaphore/try_acquire_posix.cc: Likewise.
	* testsuite/30_threads/semaphore/try_acquire_until.cc: Likewise.
	* testsuite/30_threads/latch/1.cc: New test.
	* testsuite/30_threads/latch/2.cc: New test.
	* testsuite/30_threads/latch/3.cc: New test.
	* testsuite/util/atomic/wait_notify_util.h: New File.

Here, since we only mention bar<B>, we never emit debug information for it.
But we do emit debug information for H<J>::h, so we need to refer to the
debug info for bar<B>::J even though there is no bar<B>.  We deal with this
sort of thing in dwarf2out with the limbo_die_list; parentless dies like J
get attached to the CU at EOF.  But here, we were flushing the limbo list,
then generating the template argument DIE for H<J> that refers to J, which
adds J to the limbo list, too late to be flushed.  So let's flush a little
later.

gcc/ChangeLog:

	PR c++/97918
	* dwarf2out.c (dwarf2out_early_finish): flush_limbo_die_list
	after gen_scheduled_generic_parms_dies.

gcc/testsuite/ChangeLog:

	PR c++/97918
	* g++.dg/debug/localclass2.C: New test.

gcc/c-family/ChangeLog:
	* c-warn.c (warn_parm_array_mismatch): Bail on invalid redeclarations
	with fewer arguments.

gcc/testsuite/ChangeLog:
	* gcc.dg/attr-access-4.c: New test.

Reduce memory allocation in stable_sort/inplace_merge algorithms to what is needed
by the implementation.

Co-authored-by: John Chang <john.chang@samba.tv>

libstdc++-v3/ChangeLog:

	PR libstdc++/83938
	* include/bits/stl_tempbuf.h (get_temporary_buffer): Change __len
	computation in the loop to avoid truncation.
	* include/bits/stl_algo.h:
	(__inplace_merge): Take temporary buffer length from smallest range.
	(__stable_sort): Limit temporary buffer length.
	* testsuite/25_algorithms/inplace_merge/1.cc (test4): New.
	* testsuite/performance/25_algorithms/stable_sort.cc: Test stable_sort
	under different heap memory conditions.
	* testsuite/performance/25_algorithms/inplace_merge.cc: New test.

Check for the presence of _SC_NPROCESSORS_ONLN rather than using a list
of OS-specific macros to decide whether to use `sysconf' like elsewhere
across GCC sources, fixing a compilation error:

adaint.c: In function '__gnat_number_of_cpus':
adaint.c:2398:26: error: '_SC_NPROCESSORS_ONLN' undeclared (first use in this function)
 2398 |   cores = (int) sysconf (_SC_NPROCESSORS_ONLN);
      |                          ^~~~~~~~~~~~~~~~~~~~
adaint.c:2398:26: note: each undeclared identifier is reported only once for each function it appears in

at least with with VAX/NetBSD 1.6.2.

	gcc/ada/
	* adaint.c (__gnat_number_of_cpus): Check for the presence of
	_SC_NPROCESSORS_ONLN rather than a list of OS-specific macros
	to decide whether to use `sysconf'.

Disable USE_PT_GNU_EH_FRAME frame unwinder support for old OS versions,
fixing compilation errors:

.../libgcc/unwind-dw2-fde-dip.c:75:21: error: unknown type name 'Elf_Phdr'
   75 | # define ElfW(type) Elf_##type
      |                     ^~~~
.../libgcc/unwind-dw2-fde-dip.c:132:9: note: in expansion of macro 'ElfW'
  132 |   const ElfW(Phdr) *p_eh_frame_hdr;
      |         ^~~~
.../libgcc/unwind-dw2-fde-dip.c:75:21: error: unknown type name 'Elf_Phdr'
   75 | # define ElfW(type) Elf_##type
      |                     ^~~~
.../libgcc/unwind-dw2-fde-dip.c:133:9: note: in expansion of macro 'ElfW'
  133 |   const ElfW(Phdr) *p_dynamic;
      |         ^~~~
.../libgcc/unwind-dw2-fde-dip.c:165:37: warning: 'struct dl_phdr_info' declared inside parameter list will not be visible outside of this definition or declaration
  165 | _Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr)
      |                                     ^~~~~~~~~~~~
[...]

and producing a working cross-compiler at least with VAX/NetBSD 1.6.2.

	libgcc/
	* unwind-dw2-fde-dip.c [__OpenBSD__ || __NetBSD__]
	(USE_PT_GNU_EH_FRAME): Do not define if !TARGET_DL_ITERATE_PHDR.

gcc/c-family/ChangeLog:

	PR middle-end/97879
	* c-attribs.c (handle_access_attribute): Handle ATTR_FLAG_INTERNAL.
	Error out on invalid modes.

gcc/c/ChangeLog:
	PR middle-end/97879
	* c-decl.c (start_function): Set ATTR_FLAG_INTERNAL in flags.

gcc/ChangeLog:

	PR middle-end/97879
	* tree-core.h (enum attribute_flags): Add ATTR_FLAG_INTERNAL.

gcc/testsuite/ChangeLog:

	PR middle-end/97879
	* gcc.dg/attr-access-3.c: New test.

Overhaul the mangling scheme to avoid ambiguities if the package path
contains a dot. Instead of using dot both to separate components and
to mangle characters, use dot only to separate components and use
underscore to mangle characters.

For golang/go#41862

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/271726

Use new template parameters to replace usage of lambdas to move or not
tree values on copy.

libstdc++-v3/ChangeLog:

	* include/bits/move.h (_GLIBCXX_FWDREF): New.
	* include/bits/stl_tree.h: Adapt to use latter.
	(_Rb_tree<>::_M_clone_node): Add _MoveValue template parameter.
	(_Rb_tree<>::_M_mbegin): New.
	(_Rb_tree<>::_M_begin): Use latter.
	(_Rb_tree<>::_M_copy): Add _MoveValues template parameter.
	* testsuite/23_containers/map/allocator/move_cons.cc: New test.
	* testsuite/23_containers/multimap/allocator/move_cons.cc: New test.
	* testsuite/23_containers/multiset/allocator/move_cons.cc: New test.
	* testsuite/23_containers/set/allocator/move_cons.cc: New test.

Another remaining case is that we end up comparing calls with mismatching
number of parameters or with different permutations of them.

This is because we hash decls to nothing. This patch improves that by
hashing decls by their code and parm decls by indexes that are stable.
Also for defualt defs in SSA_NAMEs we can add the corresponding decl (that
is usually parm decls).

Still we could improve on this by hasing ssa names by their definit parameters
and possibly making maps of other decls and assigning them stable function
local IDs.

	* ipa-icf-gimple.c (func_checker::hash_operand): Improve hashing of
	decls.

one of common remaining reasons for ICF to fail after loading in fuction
body is mismatched type of automatic vairable.   This is becuase
compatible_types_p resorts to checking TYPE_MAIN_VARIANTS for
euqivalence that prevents merging many TBAA compaitle cases.  (And thus
is also not reflected by the hash extended by alias sets of accesses.)

Since in gimple
automatic variables are just blocks of memory I think we should only
check its size only. All accesses are matched when copmparing the actual
loads/stores.

I am not sure if we need to match types of other DECLs but I decided I can try
to be safe here: for PARM_DECl/RESUILT_DECL we match them anyway to be sure
that functions are ABI compatible.  For CONST_DECL and readonly global
VAR_DECLs they are matched when comparing their constructors.

	* ipa-icf-gimple.c (func_checker::compare_decl): Do not compare types
	of local variables.

Adjust testcase to check in CCP not EVRP.

	gcc/testuite/
	* gcc.dg/pr97515.c: Check in ccp2, not evrp.

gcc/testsuite/ChangeLog

2020-11-09  Andrea Corallo  <andrea.corallo@arm.com>

	PR target/97727
	* gcc.target/aarch64/advsimd-intrinsics/bf16_vstN_lane_2.c: Relax
	regexps.

I noticed a couple of places we used @code{program} instead of
@command{program}.

	gcc/
	* doc/invoke.texi: Replace a couple of @code with @command

2020-11-10  Andrea Corallo  <andrea.corallo@arm.com>

	PR target/97726
	* gcc.target/arm/simd/bf16_vldn_1.c: Relax regexps not to fail on
	big endian.
	* gcc.target/arm/simd/vldn_lane_bf16_1.c: Likewise
	* gcc.target/arm/simd/vmmla_1.c: Add -mfloat-abi=hard flag.

This modifies vectorizable_slp_permutation to update the type of the children
of a perm node before trying to permute them.  This allows us to be able to
permute invariant nodes.

This will be covered by test from the SLP pattern matcher.

gcc/ChangeLog:

	* tree-vect-slp.c (vectorizable_slp_permutation): Update types on nodes
	when needed.

Unlike the other headers that declare alias templates in namespace pmr,
<regex> includes <memory_resource>. That was done because the
pmr::string::const_iterator typedef requires pmr::string to be complete,
which requires pmr::polymorphic_allocator<char> to be complete.

By using __normal_iterator<const char*, pmr::string> instead of the
const_iterator typedef we can avoid the completeness requirement.

This makes <regex> smaller, by not requiring <memory_resource> and its
<shared_mutex> dependency, which depends on <chrono>.  Backporting this
will also help with PR 97876, where <stop_token> ends up being needed by
<regex> via <memory_resource>.

libstdc++-v3/ChangeLog:

	PR libstdc++/92546
	* include/std/regex (pmr::smatch, pmr::wsmatch): Declare using
	underlying __normal_iterator type, not nested typedef
	basic_string::const_iterator.

This makes hybrid SLP discovery deal with stmts indirectly consumed
by SLP, for example via patterns.  This means that all uses of a
stmt end up in SLP vectorized stmts.

This helps my prototype patches for PR97832 where I make SLP discovery
re-associate chains to make operands match.  This ends up building
SLP computation nodes without 1:1 representatives in the scalar IL
and thus no scalar lane defs in SLP_TREE_SCALAR_STMTS.  Nevertheless
all of the original scalar stmts are consumed so this represents
another kind of SLP pattern for the computation chain result.

2020-11-20  Richard Biener  <rguenther@suse.de>

	* tree-vect-slp.c (maybe_push_to_hybrid_worklist): New function.
	(vect_detect_hybrid_slp): Use it.  Perform a backward walk
	over the IL.

It always annoyed me to see those empty SLP nodes in dumpfiles:

t.c:16:3: note:   node 0x3a2a280 (max_nunits=1, refcnt=1)
t.c:16:3: note:         { }
t.c:16:3: note:         children 0x3a29db0 0x3a29e90

resulting from two-operator handling.  The following makes
sure to also dump the operation template or VEC_PERM_EXPR.

2020-11-20  Richard Biener  <rguenther@suse.de>

	* tree-vect-slp.c (vect_print_slp_tree): Also dump
	SLP_TREE_REPRESENTATIVE.

The following patch implements __builtin_clear_padding builtin that clears
the padding bits in object representation (but preserves value
representation).  Inside of unions it clears only those padding bits that
are padding for all the union members (so that it never alters value
representation).

It handles trailing padding, padding in the middle of structs including
bitfields (PDP11 unhandled, I've never figured out how those bitfields
work), VLAs (doesn't handle variable length structures, but I think almost
nobody uses them and it isn't worth the extra complexity).  For VLAs and
sufficiently large arrays it uses runtime clearing loop instead of emitting
straight-line code (unless arrays are inside of a union).

The way I think this can be used for atomics is e.g. if the structures
are power of two sized and small enough that we use the hw atomics
for say compare_exchange __builtin_clear_padding could be called first on
the address of expected and desired arguments (for desired only if we want
to ensure that most of the time the atomic memory will have padding bits
cleared), then perform the weak cmpxchg and if that fails, we got the
value from the atomic memory; we can call __builtin_clear_padding on a copy
of that and then compare it with expected, and if it is the same with the
padding bits masked off, we can use the original with whatever random
padding bits in it as the new expected for next cmpxchg.
__builtin_clear_padding itself is not atomic and therefore it shouldn't
be called on the atomic memory itself, but compare_exchange*'s expected
argument is a reference and normally the implementation may store there
the current value from memory, so padding bits can be cleared in that,
and desired is passed by value rather than reference, so clearing is fine
too.
When using libatomic, we can use it either that way, or add new libatomic
APIs that accept another argument, pointer to the padding bit bitmask,
and construct that in the template as
  alignas (_T) unsigned char _mask[sizeof (_T)];
  std::memset (_mask, ~0, sizeof (_mask));
  __builtin_clear_padding ((_T *) _mask);
which will have bits cleared for padding bits and set for bits taking part
in the value representation.  Then libatomic could internally instead
of using memcmp compare
for (i = 0; i < N; i++) if ((val1[i] & mask[i]) != (val2[i] & mask[i]))

2020-11-20  Jakub Jelinek  <jakub@redhat.com>

	PR libstdc++/88101
gcc/
	* builtins.def (BUILT_IN_CLEAR_PADDING): New built-in function.
	* gimplify.c (gimplify_call_expr): Rewrite single argument
	BUILT_IN_CLEAR_PADDING into two-argument variant.
	* gimple-fold.c (clear_padding_unit, clear_padding_buf_size): New
	const variables.
	(struct clear_padding_struct): New type.
	(clear_padding_flush, clear_padding_add_padding,
	clear_padding_emit_loop, clear_padding_type,
	clear_padding_union, clear_padding_real_needs_padding_p,
	clear_padding_type_may_have_padding_p,
	gimple_fold_builtin_clear_padding): New functions.
	(gimple_fold_builtin): Handle BUILT_IN_CLEAR_PADDING.
	* doc/extend.texi (__builtin_clear_padding): Document.
gcc/c-family/
	* c-common.c (check_builtin_function_arguments): Handle
	BUILT_IN_CLEAR_PADDING.
gcc/testsuite/
	* c-c++-common/builtin-clear-padding-1.c: New test.
	* c-c++-common/torture/builtin-clear-padding-1.c: New test.
	* c-c++-common/torture/builtin-clear-padding-2.c: New test.
	* c-c++-common/torture/builtin-clear-padding-3.c: New test.
	* c-c++-common/torture/builtin-clear-padding-4.c: New test.
	* c-c++-common/torture/builtin-clear-padding-5.c: New test.
	* g++.dg/torture/builtin-clear-padding-1.C: New test.
	* g++.dg/torture/builtin-clear-padding-2.C: New test.
	* gcc.dg/builtin-clear-padding-1.c: New test.

The documentation for POST_MODIFY says:
   Currently, the compiler can only handle second operands of the
   form (plus (reg) (reg)) and (plus (reg) (const_int)), where
   the first operand of the PLUS has to be the same register as
   the first operand of the *_MODIFY.
The following testcase ICEs, because combine just attempts to simplify
things and ends up with
(post_modify (reg1) (plus (mult (reg2) (const_int 4)) (reg1))
but the target predicates accept it, because they only verify
that POST_MODIFY's second operand is PLUS and the second operand
of the PLUS is a REG.

The following patch fixes this by performing further verification that
the POST_MODIFY is in the form it should be.

2020-11-20  Jakub Jelinek  <jakub@redhat.com>

	PR target/97528
	* config/arm/arm.c (neon_vector_mem_operand): For POST_MODIFY, require
	first POST_MODIFY operand is a REG and is equal to the first operand
	of PLUS.

	* gcc.target/arm/pr97528.c: New test.

There is a loophole in new string store merging support added recently:
it does not check that the stores are consecutive, which is obviously
required if you want to concatenate them...  Simple fix attached, the
nice thing being that it can fall back to the regular processing if
any hole is detected in the series of stores, thanks to the handling
of STRING_CST by native_encode_expr.

gcc/ChangeLog:
	* gimple-ssa-store-merging.c (struct merged_store_group): Add
	new 'consecutive' field.
	(merged_store_group): Set it to true.
	(do_merge): Set it to false if the store is not consecutive and
	set string_concatenation to false in this case.
	(merge_into): Call do_merge on entry.
	(merge_overlapping): Likewise.

gcc/testsuite/ChangeLog:
	* gnat.dg/opt90a.adb: New test.
	* gnat.dg/opt90b.adb: Likewise.
	* gnat.dg/opt90c.adb: Likewise.
	* gnat.dg/opt90d.adb: Likewise.
	* gnat.dg/opt90e.adb: Likewise.
	* gnat.dg/opt90a_pkg.ads: New helper.
	* gnat.dg/opt90b_pkg.ads: Likewise.
	* gnat.dg/opt90c_pkg.ads: Likewise.
	* gnat.dg/opt90d_pkg.ads: Likewise.
	* gnat.dg/opt90e_pkg.ads: Likewise.

	* ipa-icf-gimple.c (func_checker::operand_equal_p): Fix comment.

after fixing few issues I gotto stage where 1.4M icf mismatches are due to
comparing two gimple clobber.  The problem is that operand_equal_p match
clobber

case CONSTRUCTOR:
 /* In GIMPLE empty constructors are allowed in initializers of
    aggregates.  */
 return !CONSTRUCTOR_NELTS (arg0) && !CONSTRUCTOR_NELTS (arg1);

But this happens too late after comparing its types (that are not very relevant
for memory store).

In the context of ipa-icf we do not really need to match RHS of gimple clobbers:
it is enough to know that the LHS stores can be considered equivalent.

I this added logic to hash them all the same way and compare using
TREE_CLOBBER_P flag.  I see other option in extending operand_equal_p
in fold-const to handle them more generously or making stmt hash and compare
to skip comparing/hashing RHS of gimple_clobber_p.

	* ipa-icf-gimple.c (func_checker::hash_operand): Hash gimple clobber.
	(func_checker::operand_equal_p): Special case gimple clobber.

The patch introduces absM named pattern to generate optimal insn sequence
for CMOVE_TARGET targets.  Currently, the expansion goes through neg+max
optabs, and the following code is generated:

	movl    %edi, %eax
	negl    %eax
	cmpl    %edi, %eax
	cmovl   %edi, %eax

This sequence is unoptimal in two ways.  a) The compare instruction is
not needed, since NEG insn sets the sign flag based on the result.
The CMOV can use sign flag to select between negated and original value:

	movl    %edi, %eax
	negl    %eax
	cmovs   %edi, %eax

b) On some targets, CMOV is undesirable due to its performance issues.
In addition to TARGET_EXPAND_ABS bypass, the patch introduces STV
conversion of abs RTX to use PABS SSE insn:

	vmovd   %edi, %xmm0
	vpabsd  %xmm0, %xmm0
	vmovd   %xmm0, %eax

The patch changes compare mode of NEG instruction to CCGOCmode,
which is the same mode as the mode of SUB instruction. IOW, sign bit
becomes usable.

Also, the mode iterator of <maxmin:code><mode>3 pattern is changed
to SWI48x instead of SWI248. The purpose of maxmin expander is to
prepare max/min RTX for STV to eventually convert them to SSE PMAX/PMIN
instructions, in order to *avoid* CMOV insns with general registers.

2020-11-20  Uroš Bizjak  <ubizjak@gmail.com>

gcc/
	PR target/97873
	* config/i386/i386.md (*neg<mode>2_2): Rename from
	"*neg<mode>2_cmpz".  Use CCGOCmode instead of CCZmode.
	(*negsi2_zext): Rename from *negsi2_cmpz_zext.
	Use CCGOCmode instead of CCZmode.
	(*neg<mode>_ccc_1): New insn pattern.
	(*neg<dwi>2_doubleword): Use *neg<mode>_ccc_1.

	(abs<mode>2): Add FLAGS_REG clobber.
	Use TARGET_CMOVE insn predicate.
	(*abs<mode>2_1): New insn_and_split pattern.
	(*absdi2_doubleword): Ditto.

	(<maxmin:code><mode>3): Use SWI48x mode iterator.
	(*<maxmin:code><mode>3): Use SWI48 mode iterator.

	* config/i386/i386-features.c
	(general_scalar_chain::compute_convert_gain): Handle ABS code.
	(general_scalar_chain::convert_insn): Ditto.
	(general_scalar_to_vector_candidate_p): Ditto.

gcc/testsuite/
	PR target/97873
	* gcc.target/i386/pr97873.c: New test.
	* gcc.target/i386/pr97873-1.c: New test.

Eric reported that the --enable-link-serialization changes seemed to
cause the binaries to be always relinked, for example from the
gcc/ directory of the build tree:
make
[relink of gnat1, brig1, cc1plus, d21, f951, go1, lto1, ...]
make
[relink of gnat1, brig1, cc1plus, d21, f951, go1, lto1, ...]
Furthermore as reported in PR, it can cause problems during make install
where make install rebuilds the binaries again.

The problem is that for make .PHONY targets are just
"rebuilt" always, so it is very much undesirable for the cc1plus$(exeext)
etc. dependencies to include .PHONY targets, but I was using
them - cc1plus.prev which would depend on some *.serial and
e.g. cc1.serial depending on c and c depending on cc1$(exeext).

The following patch rewrites this so that *.serial and *.prev aren't
.PHONY targets, but instead just make variables.

I was worried that the order in which the language makefile fragments are
included (which is quite random, what order we get from the filesystem
matching */config-lang.in) would be a problem but it seems to work fine
- as it uses make = rather than := variables, later definitions are just
fine for earlier uses as long as the uses aren't needed during the
makefile parsing, but only in the dependencies of make targets and in
their commands.

2020-11-20  Jakub Jelinek  <jakub@redhat.com>

	PR other/97911
gcc/
	* configure.ac: In SERIAL_LIST use lang words without .serial
	suffix.  Change $lang.prev from a target to variable and instead
	of depending on *.serial expand to the *.serial variable if
	the word is in the SERIAL_LIST at all, otherwise to nothing.
	* configure: Regenerated.
gcc/c/
	* Make-lang.in (c.serial): Change from goal to a variable.
	(.PHONY): Drop c.serial.
gcc/ada/
	* gcc-interface/Make-lang.in (ada.serial): Change from goal to a
	variable.
	(.PHONY): Drop ada.serial and ada.prev.
	(gnat1$(exeext)): Depend on $(ada.serial) rather than ada.serial.
gcc/brig/
	* Make-lang.in (brig.serial): Change from goal to a variable.
	(.PHONY): Drop brig.serial and brig.prev.
	(brig1$(exeext)): Depend on $(brig.serial) rather than brig.serial.
gcc/cp/
	* Make-lang.in (c++.serial): Change from goal to a variable.
	(.PHONY): Drop c++.serial and c++.prev.
	(cc1plus$(exeext)): Depend on $(c++.serial) rather than c++.serial.
gcc/d/
	* Make-lang.in (d.serial): Change from goal to a variable.
	(.PHONY): Drop d.serial and d.prev.
	(d21$(exeext)): Depend on $(d.serial) rather than d.serial.
gcc/fortran/
	* Make-lang.in (fortran.serial): Change from goal to a variable.
	(.PHONY): Drop fortran.serial and fortran.prev.
	(f951$(exeext)): Depend on $(fortran.serial) rather than
	fortran.serial.
gcc/go/
	* Make-lang.in (go.serial): Change from goal to a variable.
	(.PHONY): Drop go.serial and go.prev.
	(go1$(exeext)): Depend on $(go.serial) rather than go.serial.
gcc/jit/
	* Make-lang.in (jit.serial): Change from goal to a
	variable.
	(.PHONY): Drop jit.serial and jit.prev.
	($(LIBGCCJIT_FILENAME)): Depend on $(jit.serial) rather than
	jit.serial.
gcc/lto/
	* Make-lang.in (lto1.serial, lto2.serial): Change from goals to
	variables.
	(.PHONY): Drop lto1.serial, lto2.serial, lto1.prev and lto2.prev.
	($(LTO_EXE)): Depend on $(lto1.serial) rather than lto1.serial.
	($(LTO_DUMP_EXE)): Depend on $(lto2.serial) rather than lto2.serial.
gcc/objc/
	* Make-lang.in (objc.serial): Change from goal to a variable.
	(.PHONY): Drop objc.serial and objc.prev.
	(cc1obj$(exeext)): Depend on $(objc.serial) rather than objc.serial.
gcc/objcp/
	* Make-lang.in (obj-c++.serial): Change from goal to a variable.
	(.PHONY): Drop obj-c++.serial and obj-c++.prev.
	(cc1objplus$(exeext)): Depend on $(obj-c++.serial) rather than
	obj-c++.serial.

This patch is to fix insn type of p8_mtvsrd_df from mfvsr to mtvsr,
in order to align with the other places using mtvsrd.

gcc/ChangeLog:

	* config/rs6000/rs6000.md (p8_mtvsrd_df): Fix insn type.

2020-11-20  Martin Uecker  <muecker@gwdg.de>

gcc/
	* gimplify.c (gimplify_modify_expr_rhs): Optimizie
	NOP_EXPRs that contain compound literals.

gcc/c/
	* c-typeck.c (convert_lvalue_to_rvalue): Drop qualifiers.

gcc/testsuite/
	* gcc.dg/cond-constqual-1.c: Adapt test.
	* gcc.dg/lvalue-11.c: New test.
	* gcc.dg/pr60195.c: Add warning.

As mentioned in the PR, the previous PR91029 patch was testing
op2 >= 0 which is unnecessary, even negative op2 values will work the same,
furthermore, from if a % b > 0 we can deduce a > 0 rather than just a >= 0
(0 % b would be 0), and it actually valid even for other constants than 0,
a % b > 5 means a > 5 (a % b has the same sign as a and a in [0, 5] would
result in a % b in [0, 5].  Also, we can deduce a range for the other
operand, if we know
a % b >= 20, then b must be (in absolute value for signed modulo) > 20,
for a % [0, 20] the result would be [0, 19].

2020-11-19  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/91029
	* range-op.cc (operator_trunc_mod::op1_range): Don't require signed
	types, nor require that op2 >= 0.  Implement (a % b) >= x && x > 0
	implies a >= x and (a % b) <= x && x < 0 implies a <= x.
	(operator_trunc_mod::op2_range): New method.

	* gcc.dg/tree-ssa/pr91029-1.c: New test.
	* gcc.dg/tree-ssa/pr91029-2.c: New test.

When shifting outside the valid range of [0, precision-1], we can
choose to process just the valid ones since the rest is undefined.
this allows us to produce results for x << [0,2][+INF, +INF] by discarding
the invalid ranges and processing just [0,2].

	gcc/
	PR tree-optimization/93781
	* range-op.cc (get_shift_range): Rename from
	undefined_shift_range_check and now return valid shift ranges.
	(operator_lshift::fold_range): Use result from get_shift_range.
	(operator_rshift::fold_range): Ditto.
	gcc/testsuite/
	* gcc.dg/tree-ssa/pr93781-1.c: New.
	* gcc.dg/tree-ssa/pr93781-2.c: New.
	* gcc.dg/tree-ssa/pr93781-3.c: New.

This exposes the template specialization table, so the modules
machinery may access it.  The hashed entity (tmpl, args & spec) is
available, along with a hash table walker.  We also need a way of
finding or inserting entries, along with some bookkeeping fns to deal
with the instantiation and (partial) specialization lists.

	gcc/cp/
	* cp-tree.h (struct spec_entry): Moved from pt.c.
	(walk_specializations, match_mergeable_specialization)
	(get_mergeable_specialization_flags)
	(add_mergeable_specialization): Declare.
	* pt.c (struct spec_entry): Moved to cp-tree.h.
	(walk_specializations, match_mergeable_specialization)
	(get_mergeable_specialization_flags)
	(add_mergeable_specialization): New.

Since glibc 2.27 the pthread_self symbol has been defined in libc rather
than libpthread. Because we only call pthread_self through a weak alias
it's possible for statically linked executables to end up without a
definition of pthread_self. This crashes when trying to call an
undefined weak symbol.

We can use the __GLIBC_PREREQ version check to detect the version of
glibc where pthread_self is no longer in libpthread, and call it
directly rather than through the weak reference.

It would be better to check for pthread_self in libc during configure
instead of hardcoding the __GLIBC_PREREQ check. That would be
complicated by the fact that prior to glibc 2.27 libc.a didn't have the
pthread_self symbol, but libc.so.6 did.  The configure checks would need
to try to link both statically and dynamically, and the result would
depend on whether the static libc.a happens to be installed during
configure (which could vary between different systems using the same
version of glibc). Doing it properly is left for a future date, as that
will be needed anyway after glibc moves all pthread symbols from
libpthread to libc. When that happens we should revisit the whole
approach of using weak symbols for pthread symbols.

For the purposes of std::this_thread::get_id() we call
pthread_self() directly when using glibc 2.27 or later. Otherwise, if
__gthread_active_p() is true then we know the libpthread symbol is
available so we call that. Otherwise, we are single-threaded and just
use ((__gthread_t)1) as the thread ID.

An undesirable consequence of this change is that code compiled prior to
the change might inline the old definition of this_thread::get_id()
which always returns (__gthread_t)1 in a program that isn't linked to
libpthread. Code compiled after the change will use pthread_self() and
so get a real TID. That could result in the main thread having different
thread::id values in different translation units. This seems acceptable,
as there are not expected to be many uses of thread::id in programs
that aren't linked to libpthread.

An earlier version of this patch also changed __gthread_self() to use
__GLIBC_PREREQ(2, 27) and only use the weak symbol for older glibc. Tha
might still make sense to do, but isn't needed by libstdc++ now.

libstdc++-v3/ChangeLog:

	PR libstdc++/95989
	* config/os/gnu-linux/os_defines.h (_GLIBCXX_NATIVE_THREAD_ID):
	Define new macro to get reliable thread ID.
	* include/bits/std_thread.h: (this_thread::get_id): Use new
	macro if it's defined.
	* testsuite/30_threads/jthread/95989.cc: New test.
	* testsuite/30_threads/this_thread/95989.cc: New test.