PR target/104688

libatomic/ChangeLog:

	* config/x86/init.c (__libat_feat1_init): Don't clear
	bit_AVX on ZHAOXIN CPUs.

Check the result of __get_cpuid and process FEAT1_REGISTER only when
__get_cpuid returns success.  Use __cpuid instead of nested __get_cpuid.

libatomic/ChangeLog:

	* config/x86/init.c (__libat_feat1_init): Check the result of
	__get_cpuid and process FEAT1_REGISTER only when __get_cpuid
	returns success.  Use __cpuid instead of nested __get_cpuid.

The introduction of the optional RCPC3 architectural extension for
Armv8.2-A upwards provides additional support for the release
consistency model, introducing the Load-Acquire RCpc Pair Ordered, and
Store-Release Pair Ordered operations in the form of LDIAPP and STILP.

These operations are single-copy atomic on cores which also implement
LSE2 and, as such, support for these operations is added to Libatomic
and employed accordingly when the LSE2 and RCPC3 features are detected
in a given core at runtime.

libatomic/ChangeLog:

	* config/linux/aarch64/atomic_16.S (libat_load_16): Add LRCPC3
	variant.
	(libat_store_16): Likewise.
	* config/linux/aarch64/host-config.h (HWCAP2_LRCPC3): New.
	(LSE2_LRCPC3_ATOP): Previously LSE2_ATOP.  New ifuncs guarded
	under it.
	(has_rcpc3): New.

At present, `atomic_16.S' groups different implementations of the
same functions together in the file.  Therefore, as an example,
the LSE2 implementation of `load_16' follows on immediately from its
core implementation, as does the `store_16' LSE2 implementation.

Such architectural extension-dependent implementations are dependent
on ifunc support, such that they are guarded by the relevant
preprocessor macro, i.e.  `#if HAVE_IFUNC'.

Having to apply these guards on a per-function basis adds unnecessary
clutter to the file and makes its maintenance more error-prone.

We therefore reorganize the layout of the file in such a way that all
core implementations needing no `#ifdef's are placed first, followed
by all ifunc-dependent implementations, which can all be guarded by a
single `#if HAVE_IFUNC', greatly reducing the overall number of
required `#ifdef' macros.

libatomic/ChangeLog:

	* config/linux/aarch64/atomic_16.S: Reorganize functions in
	file.
	(HAVE_FEAT_LSE2): Delete.

By querying previously-defined file-identifier macros, `host-config.h'
is able to get information about its environment and, based on this
information, select more appropriate function-specific ifunc
selectors.  This reduces the number of unnecessary feature tests that
need to be carried out in order to find the best atomic implementation
for a function at run-time.

An immediate benefit of this is that we can further fine-tune the
architectural requirements for each atomic function without risk of
incurring the maintenance and runtime-performance penalties of having
to maintain an ifunc selector with a huge number of alternatives, most
of which are irrelevant for any particular function.  Consequently,
for AArch64 targets, we relax the architectural requirements of
`compare_exchange_16', which now requires only LSE as opposed to the
newer LSE2.

The new flexibility provided by this approach also means that certain
functions can now be called directly, doing away with ifunc selectors
altogether when only a single implementation is available for it on a
given target.  As per the macro expansion framework laid out in
`libatomic_i.h', such functions should have their names prefixed with
`__atomic_' as opposed to `libat_'.  This is the same prefix applied
to function names when Libatomic is configured with
`--disable-gnu-indirect-function'.

To achieve this, these functions unconditionally apply the aliasing
rule that at present is conditionally applied only when libatomic is
built without ifunc support, which ensures that the default
`libat_##NAME' is accessible via the equivalent `__atomic_##NAME' too.
This is ensured by using the new `ENTRY_ALIASED' macro.

Finally, this means we are able to do away with a whole set of
function aliases that were needed until now, thus considerably
cleaning up the implementation.

libatomic/ChangeLog:

	* config/linux/aarch64/atomic_16.S: Remove unnecessary
	aliasing.
	(LSE): New.
	(ENTRY_ALIASED): Likewise.
	* config/linux/aarch64/host-config.h (LSE_ATOP): New.
	(LSE2_ATOP): Likewise.
	(LSE128_ATOP): Likewise.
	(IFUNC_COND_1): Make its definition conditional on above 3
	macros.
	(IFUNC_NCOND): Likewise.

In order to facilitate the fine-tuning of how `libatomic_i.h' and
`host-config.h' headers are used by different atomic functions, we
define distinct identifier macros for each file which, in implementing
atomic operations, imports these headers.

The idea is that different parts of these headers could then be
conditionally defined depending on the macros set by the file that
`#include'd them.

Given how it is possible that some file names are generic enough that
using them as-is for macro names (e.g. flag.c -> FLAG) may potentially
lead to name clashes with other macros, all file names first have LAT_
prepended to them such that, for example, flag.c is assigned the
LAT_FLAG macro.

Libatomic/ChangeLog:

	* cas_n.c (LAT_CAS_N): New.
	* exch_n.c (LAT_EXCH_N): Likewise.
	* fadd_n.c (LAT_FADD_N): Likewise.
	* fand_n.c (LAT_FAND_N): Likewise.
	* fence.c (LAT_FENCE): Likewise.
	* fenv.c (LAT_FENV): Likewise.
	* fior_n.c (LAT_FIOR_N): Likewise.
	* flag.c (LAT_FLAG): Likewise.
	* fnand_n.c (LAT_FNAND_N): Likewise.
	* fop_n.c (LAT_FOP_N): Likewise
	* fsub_n.c (LAT_FSUB_N): Likewise.
	* fxor_n.c (LAT_FXOR_N): Likewise.
	* gcas.c (LAT_GCAS): Likewise.
	* gexch.c (LAT_GEXCH): Likewise.
	* glfree.c (LAT_GLFREE): Likewise.
	* gload.c (LAT_GLOAD): Likewise.
	* gstore.c (LAT_GSTORE): Likewise.
	* load_n.c (LAT_LOAD_N): Likewise.
	* store_n.c (LAT_STORE_N): Likewise.
	* tas_n.c (LAT_TAS_N): Likewise.

Given the lack of support for the LSE128 instructions in all but the
the most up-to-date version of Binutils (2.42), having the build-time
test for assembler support for these instructions often leads to the
building of Libatomic without support for LSE128-dependent atomic
function implementations.  This ultimately leads to different people
having different versions of Libatomic on their machines, depending on
which assembler was available at compilation time.

Furthermore, the conditional inclusion of these atomic function
implementations predicated on assembler support leads to a series of
`#if HAVE_FEAT_LSE128' guards scattered throughout the codebase and
the need for a series of aliases when the feature flag evaluates
to false.  The preprocessor macro guards, together with the
conditional aliasing leads to code that is cumbersome to understand
and maintain.

Both of the issues highlighted above will only get worse with the
coming support for LRCPC3 atomics which under the current scheme will
also require build-time checks.

Consequently, a better option for both consistency across builds and
code cleanness is to make recourse to the `.inst' directive.  By
replacing all novel assembly instructions for their hexadecimal
representation within `.inst's, we ensure that the Libatomic code is
both considerably cleaner and all machines build the same binary,
irrespective of binutils version available at compile time.

This patch therefore removes all configure checks for LSE128-support
in the assembler and all the guards and aliases that were associated
with `HAVE_FEAT_LSE128'

libatomic/ChangeLog:

	* acinclude.m4 (LIBAT_TEST_FEAT_AARCH64_LSE128): Delete.
	* auto-config.h.in (HAVE_FEAT_LSE128): Likewise
	* config/linux/aarch64/atomic_16.S: Replace all LSE128
	instructions with equivalent `.inst' directives.
	(HAVE_FEAT_LSE128): Remove all references.
	* configure: Regenerate.
	* configure.ac: Remove call to LIBAT_TEST_FEAT_AARCH64_LSE128.

A recent patch

commit bdc264a1
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Thu May 30 02:06:48 2024 -0300

    [testsuite] conditionalize dg-additional-sources on target and type

added two additional args to dg-additional-files-options.
Unfortunately, this completely broke several testsuites like

ERROR: tcl error sourcing /vol/gcc/src/hg/master/local/libatomic/testsuite/../../gcc/testsuite/lib/gcc-dg.exp.
wrong # args: should be "dg-additional-files-options options source dest type"

since the patch forgot to adjust some of the callers.

This patch fixes that.

Tested on i386-pc-solaris2.11, sparc-sun-solaris2.11, and
x86_64-pc-linux-gnu.

2024-05-31  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	libatomic:
	PR testsuite/115294
	* testsuite/lib/libatomic.exp (libatomic_target_compile): Pass new
	dg-additional-files-options args.

	libgomp:
	PR testsuite/115294
	* testsuite/lib/libgomp.exp (libgomp_target_compile): Pass new
	dg-additional-files-options args.

	libitm:
	PR testsuite/115294
	* testsuite/lib/libitm.exp (libitm_target_compile): Pass new
	dg-additional-files-options args.

	libphobos:
	PR testsuite/115294
	* testsuite/lib/libphobos.exp (libphobos_target_compile): Pass new
	dg-additional-files-options args.

	libvtv:
	PR testsuite/115294
	* testsuite/lib/libvtv.exp (libvtv_target_compile): Pass new
	dg-additional-files-options args.

libatomic/ChangeLog:

	* configure.tgt: Add aarch64-w64-mingw32 target.

The recent move of libgfortran object files to subdirs and the resulting
breakage of libgfortran.so symbol exports demonstrated how fragile
deriving object and archive names from their libtool counterparts in the
Makefiles is.  Therefore, this patch moves that step into
make_sunver.pl, considerably simplifying the Makefile rules to create
the version scripts.

Bootstrapped without regressions on i386-pc-solaris2.11 and
sparc-sun-solaris2.11, verifying that the version scripts are identical
except for the input filenames.

2024-05-06  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	contrib:
	* make_sunver.pl: Use File::Basename;
	Skip -lLIB args.
	Convert libtool object/archive names to underlying
	objects/archives.

	libatomic:
	* Makefile.am [LIBAT_BUILD_VERSIONED_SHLIB_SUN]
	(libatomic.map-sun): Pass $(libatomic_la_OBJECTS),
	$(libatomic_la_LIBADD) to make_sunver.pl unmodified.
	* Makefile.in: Regenerate.

	libffi:
	* Makefile.am [LIBFFI_BUILD_VERSIONED_SHLIB_SUN] (libffi.map-sun):
	Pass $(libffi_la_OBJECTS), $(libffi_la_LIBADD) to make_sunver.pl
	unmodified.
	* Makefile.in: Regenerate.

	libgfortran:
	* Makefile.am [LIBGFOR_USE_SYMVER_SUN} (gfortran.ver-sun): Pass
	$(libgfortran_la_OBJECTS), $(libgfortran_la_LIBADD) to
	make_sunver.pl unmodified.
	* Makefile.in: Regenerate.

	libgomp:
	* Makefile.am [LIBGOMP_BUILD_VERSIONED_SHLIB_SUN]
	(libgomp.ver-sun): Pass $(libgomp_la_OBJECTS),
	$(libgomp_la_LIBADD) to make_sunver.pl unmodified.
	* Makefile.in: Regenerate.

	libitm:
	* Makefile.am [LIBITM_BUILD_VERSIONED_SHLIB_SUN] (libitm.map-sun):
	Pass $(libitm_la_OBJECTS), $(libitm_la_LIBADD) to make_sunver.pl
	unmodified.
	* Makefile.in: Regenerate.

	libquadmath:
	* Makefile.am [LIBQUAD_USE_SYMVER_SUN] (quadmath.map-sun): Pass
	$(libquadmath_la_OBJECTS), $(libquadmath_la_LIBADD) to
	make_sunver.pl unmodified.
	* Makefile.in: Regenerate.

	libssp:
	* Makefile.am [LIBSSP_USE_SYMVER_SUN] (ssp.map-sun): Pass
	$(libssp_la_OBJECTS), $(libssp_la_LIBADD) to make_sunver.pl
	unmodified.
	* Makefile.in: Regenerate.

	libstdc++-v3:
	* src/Makefile.am [ENABLE_SYMVERS_SUN]
	(libstdc++-symbols.ver-sun): Pass $(libstdc___la_OBJECTS),
	$(libstdc___la_LIBADD) to make_sunver.pl unmodified.
	* src/Makefile.in: Regenerate.

Cleanup the macros to add the libat_ prefixes in atomic_16.S.  Emit the
alias to __atomic_<op> when ifuncs are not enabled in the ENTRY macro.

libatomic:
	* config/linux/aarch64/atomic_16.S: Add __libat_ prefix in the
	LSE2/LSE128/CORE macros, remove elsewhere.  Add ATOMIC macro.

Seems configure hasn't been regenerated properly after the last
acinclude.m4 change.

2024-04-05  Jakub Jelinek  <jakub@redhat.com>

	* configure: Regenerate.

Fix libatomic build to support --disable-gnu-indirect-function on AArch64.
Always build atomic_16.S, add aliases to the __atomic_ functions if !HAVE_IFUNC.
Include auto-config.h in atomic_16.S to avoid having to pass defines via
makefiles.  Fix build if HWCAP_ATOMICS/CPUID are not defined.

libatomic:
	PR target/113986
	* Makefile.in: Regenerated.
	* Makefile.am: Make atomic_16.S not depend on HAVE_IFUNC.
	Remove predefine of HAVE_FEAT_LSE128.
	* acinclude.m4: Remove ARCH_AARCH64_HAVE_LSE128.
	* configure: Regenerated.
	* config/linux/aarch64/atomic_16.S: Add __atomic_ alias if !HAVE_IFUNC.
	* config/linux/aarch64/host-config.h: Correctly handle !HAVE_IFUNC.
	Add defines for HWCAP_ATOMICS and HWCAP_CPUID.

This patch is a revised version of the fix for PR other/113336.
Bootstrapping GCC on arm-linux-gnueabihf with --with-arch=armv6 currently
has a large number of FAILs in libatomic (regressions since last time I
attempted this).  The failure mode is related to IFUNC handling with the
file tas_8_2_.o containing an unresolved reference to the function
libat_test_and_set_1_i2.

The following one line change, to build tas_1_2_.o when building tas_8_2_.o,
resolves the problem for me and restores the libatomic testsuite to 44
expected passes and 5 unsupported tests [from 22 unexpected failures
and 22 unresolved testcases].
`

2024-02-14  Roger Sayle  <roger@nextmovesoftware.com>
	    Victor Do Nascimento  <victor.donascimento@arm.com>

libatomic/ChangeLog
	PR other/113336
	* Makefile.am: Build tas_1_2_.o on ARCH_ARM_LINUX
	* Makefile.in: Regenerate.

The exception defines in <fenv.h> do not match the exception bits
in the FPU status register on hppa-linux and hppa64-hpux11.11.  On
linux, they match the trap enable bits.  On 64-bit hpux, they match
the exception bits for IA64.  The IA64 bits are in a different
order and location than HPPA.  HP uses table look ups to reorder
the bits in code to test and raise exceptions.

All the architectures that I looked at just pass the FPU status
register to __atomic_feraiseexcept().  The simplest approach for
hppa is to define FE_INEXACT, etc, to match the status register
and not include <fenv.h>..

2024-02-03  John David Anglin  <danglin@gcc.gnu.org>

libatomic/ChangeLog:

	PR target/59778
	* configure.tgt (hppa*): Set ARCH.
	* config/pa/fenv.c: New file.

At present, Evaluation of both `has_lse2(hwcap)' and
`has_lse128(hwcap)' may require issuing an `mrs' instruction to query
a system register.  This instruction, when issued from user-space
results in a trap by the kernel which then returns the value read in
by the system register.  Given the undesirable nature of the
computational expense associated with the context switch, it is
important to implement mechanisms to, wherever possible, forgo the
operation.

In light of this, given how other architectural requirements serving
as prerequisites have long been assigned HWCAP bits by the kernel, we
can inexpensively query for their availability before attempting to
read any system registers.  Where one of these early tests fail, we
can assert that the main feature of interest (be it LSE2 or LSE128)
cannot be present, allowing us to return from the function early and
skip the unnecessary expensive kernel-mediated access to system
registers.

libatomic/ChangeLog:

	* config/linux/aarch64/host-config.h (has_lse2): Add test for LSE.
	(has_lse128): Add test for LSE2.

The armv9.4-a architectural revision adds three new atomic operations
associated with the LSE128 feature:

  * LDCLRP - Atomic AND NOT (bitclear) of a location with 128-bit
  value held in a pair of registers, with original data loaded into
  the same 2 registers.
  * LDSETP - Atomic OR (bitset) of a location with 128-bit value held
  in a pair of registers, with original data loaded into the same 2
  registers.
  * SWPP - Atomic swap of one 128-bit value with 128-bit value held
  in a pair of registers.

It is worth noting that in keeping with existing 128-bit atomic
operations in `atomic_16.S', we have chosen to merge certain
less-restrictive orderings into more restrictive ones.  This is done
to minimize the number of branches in the atomic functions, minimizing
both the likelihood of branch mispredictions and, in keeping code
small, limit the need for extra fetch cycles.

Past benchmarking has revealed that acquire is typically slightly
faster than release (5-10%), such that for the most frequently used
atomics (CAS and SWP) it makes sense to add support for acquire, as
well as release.

Likewise, it was identified that combining acquire and release typically
results in little to no penalty, such that it is of negligible benefit
to distinguish between release and acquire-release, making the
combining release/acq_rel/seq_cst a worthwhile design choice.

This patch adds the logic required to make use of these when the
architectural feature is present and a suitable assembler available.

In order to do this, the following changes are made:

  1. Add a configure-time check to check for LSE128 support in the
  assembler.
  2. Edit host-config.h so that when N == 16, nifunc = 2.
  3. Where available due to LSE128, implement the second ifunc, making
  use of the novel instructions.
  4. For atomic functions unable to make use of these new
  instructions, define a new alias which causes the _i1 function
  variant to point ahead to the corresponding _i2 implementation.

libatomic/ChangeLog:

	* Makefile.am (AM_CPPFLAGS): add conditional setting of
	-DHAVE_FEAT_LSE128.
	* acinclude.m4 (LIBAT_TEST_FEAT_AARCH64_LSE128): New.
	* config/linux/aarch64/atomic_16.S (LSE128): New macro
	definition.
	(libat_exchange_16): New LSE128 variant.
	(libat_fetch_or_16): Likewise.
	(libat_or_fetch_16): Likewise.
	(libat_fetch_and_16): Likewise.
	(libat_and_fetch_16): Likewise.
	* config/linux/aarch64/host-config.h (IFUNC_COND_2): New.
	(IFUNC_NCOND): Add operand size checking.
	(has_lse2): Renamed from `ifunc1`.
	(has_lse128): New.
	(HWCAP2_LSE128): Likewise.
	* configure.ac: Add call to
	LIBAT_TEST_FEAT_AARCH64_LSE128.
	* configure (ac_subst_vars): Regenerated via autoreconf.
	* Makefile.in: Likewise.
	* auto-config.h.in: Likewise.

With support for new atomic features in Armv9.4-a being indicated by
HWCAP2 bits, Libatomic's ifunc resolver must now query its second
argument, of type __ifunc_arg_t*.

We therefore make this argument known to libatomic, allowing us to
query hwcap2 bits in the following manner:

  bool
  resolver (unsigned long hwcap, const __ifunc_arg_t *features);
  {
    return (features->hwcap2 & HWCAP2_<FEAT_NAME>);
  }

libatomic/ChangeLog:

	* config/linux/aarch64/host-config.h (__ifunc_arg_t):
	Conditionally-defined if `sys/ifunc.h' not found.
	(_IFUNC_ARG_HWCAP): Likewise.
	(IFUNC_COND_1): Pass __ifunc_arg_t argument to ifunc.
	(ifunc1): Modify function signature to accept __ifunc_arg_t
	argument.
	* configure.tgt: Add second `const __ifunc_arg_t *features'
	argument to IFUNC_RESOLVER_ARGS.

The introduction of further architectural-feature dependent ifuncs
for AArch64 makes hard-coding ifunc `_i<n>' suffixes to functions
cumbersome to work with.  It is awkward to remember which ifunc maps
onto which arch feature and makes the code harder to maintain when new
ifuncs are added and their suffixes possibly altered.

This patch uses pre-processor `#define' statements to map each suffix to
a descriptive feature name macro, for example:

  #define LSE(NAME) NAME##_i1

Where we wish to generate ifunc names with the pre-processor's token
concatenation feature, we add a level of indirection to previous macro
calls.  If before we would have had`MACRO(<name>_i<n>)', we now have
`MACRO_FEAT(name, feature)'.  Where we wish to refer to base
functionality (i.e., functions where ifunc suffixes are absent), the
original `MACRO(<name>)' may be used to bypass suffixing.

Consequently, for base functionality, where the ifunc suffix is
absent, the macro interface remains the same.  For example, the entry
and endpoints of `libat_store_16' remain defined by:

  ENTRY (libat_store_16)

and

  END (libat_store_16)

For the LSE2 implementation of the same 16-byte atomic store, we now
have:

  ENTRY_FEAT (libat_store_16, LSE2)

and

  END_FEAT (libat_store_16, LSE2)

For the aliasing of function names, we define the following new
implementation of the ALIAS macro:

  ALIAS (FN_BASE_NAME, FROM_SUFFIX, TO_SUFFIX)

Defining the `CORE(NAME)' macro to be the identity operator, it
returns the base function name unaltered and allows us to alias
target-specific ifuncs to the corresponding base implementation.
For example, we'd alias the LSE2 `libat_exchange_16' to it base
implementation with:

  ALIAS (libat_exchange_16, LSE2, CORE)

libatomic/ChangeLog:
	* config/linux/aarch64/atomic_16.S (CORE): New macro.
	(LSE2): Likewise.
	(ENTRY_FEAT): Likewise.
	(ENTRY_FEAT1): Likewise.
	(END_FEAT): Likewise.
	(END_FEAT1): Likewise.
	(ALIAS): Modify macro to take in `arch' arguments.
	(ALIAS1): New.

I need to use this cleanup logic for the testsuite for libdiagnostics
where it's too awkward to directly use gcc-dg.exp itself.

No functional change intended.

gcc/testsuite/ChangeLog:
	* lib/dg-test-cleanup.exp: New file, from material moved from
	lib/gcc-dg.exp.
	* lib/gcc-dg.exp: Add load_lib of dg-test-cleanup.exp.
	(cleanup-after-saved-dg-test): Move to lib/dg-test-cleanup.exp.
	(dg-test): Likewise for override.
	(initialize_prune_notes): Likewise.

libatomic/ChangeLog:
	* testsuite/lib/libatomic.exp: Add
	"load_gcc_lib dg-test-cleanup.exp".

libgomp/ChangeLog:
	* testsuite/lib/libgomp.exp: Add
	"load_gcc_lib dg-test-cleanup.exp".
libitm/ChangeLog:
	* testsuite/lib/libitm.exp: Add
	"load_gcc_lib dg-test-cleanup.exp".

libphobos/ChangeLog:
	* testsuite/lib/libphobos-dg.exp: Add
	"load_gcc_lib dg-test-cleanup.exp".

libstdc++-v3/ChangeLog:
	* testsuite/lib/libstdc++.exp: Add
	"load_gcc_lib dg-test-cleanup.exp".

libvtv/ChangeLog:
	* testsuite/lib/libvtv.exp: Add
	"load_gcc_lib dg-test-cleanup.exp".

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

libatomic/ChangeLog:

	* config/linux/aarch64/atomic_16.S (FEATURE_1_GCS): Define.
	(GCS_FLAG): Define if GCS is enabled.
	(GNU_PROPERTY): Add GCS_FLAG.

Since r15-3254-g3f51f0dc88ec21c1ec79df694200f10ef85915f4
added scan-ltrans-rtl* variants to scanltranstree.exp, it no longer
makes sense to have "tree" in the name.  This renames the file
accordingly and updates users.

libatomic/ChangeLog:

	* testsuite/lib/libatomic.exp: Load scanltrans.exp instead of
	scanltranstree.exp.

libgomp/ChangeLog:

	* testsuite/lib/libgomp.exp: Load scanltrans.exp instead of
	scanltranstree.exp.

libitm/ChangeLog:

	* testsuite/lib/libitm.exp: Load scanltrans.exp instead of
	scanltranstree.exp.

libphobos/ChangeLog:

	* testsuite/lib/libphobos-dg.exp: Load scanltrans.exp instead of
	scanltranstree.exp.

libvtv/ChangeLog:

	* testsuite/lib/libvtv.exp: Load scanltrans.exp instead of
	scanltranstree.exp.

gcc/testsuite/ChangeLog:

	* gcc.dg-selftests/dg-final.exp: Load scanltrans.exp instead of
	scanltranstree.exp.
	* lib/gcc-dg.exp: Likewise.
	* lib/scanltranstree.exp: Rename to ...
	* lib/scanltrans.exp: ... this.

2023 -> 2024

Enable lock-free 128-bit atomics on AArch64.  This is backwards compatible with
existing binaries (as for these GCC always calls into libatomic, so all 128-bit
atomic uses in a process are switched), gives better performance than locking
atomics and is what most users expect.

128-bit atomic loads use a load/store exclusive loop if LSE2 is not supported.
This results in an implicit store which is invisible to software as long as the
given address is writeable (which will be true when using atomics in real code).

This doesn't yet change __atomic_is_lock_free eventhough all atomics are finally
lock-free on AArch64.

libatomic:
	* config/linux/aarch64/atomic_16.S: Implement lock-free ARMv8.0 atomics.
	(libat_exchange_16): Merge RELEASE and ACQ_REL/SEQ_CST cases.
	* config/linux/aarch64/host-config.h: Use atomic_16.S for baseline v8.0.