The C++20 draft and SD-6 both say this should only be in <version> and
<algorithm>, not in <utility>.

	* include/std/utility (__cpp_lib_constexpr_algorithms): Do not define
	here.
	* testsuite/20_util/exchange/constexpr.cc: Do not expect macro to be
	defined by <utility>.

	* include/std/functional (__cpp_lib_concepts): Update macro value to
	indicate P1964R2 support.
	* include/std/version (__cpp_lib_concepts): Likewise.
	* testsuite/std/concepts/1.cc: Adjust expected value.
	* testsuite/std/concepts/2.cc: Likewise.

This macro was renamed after it was added to the working draft, but we
never renamed it  in libstdc++. We haven't made a release with the old
macro name, so I see no need to keep it around.

	* include/std/functional (__cpp_lib_constexpr_invoke): Rename to
	__cpp_lib_constexpr_functional.
	* include/std/version (__cpp_lib_constexpr_invoke): Likewise.
	* testsuite/20_util/function_objects/invoke/constexpr.cc: Adjust.

These macros all correspond to features that are already supported, but
the macro was not defined when the feature was implemented.

	* include/bits/ptr_traits.h (__cpp_lib_constexpr_memory): Define to
	indicate P1006R1 support.
	(__cpp_lib_to_address): Define to indicate P0653R2 support.
	* include/bits/range_access.h (__cpp_lib_ssize): Define to indicate
	P1227R2 support.
	* include/bits/ranges_algo.h (__cpp_lib_shift): Define to indicate
	P0769R2 support.
	* include/std/atomic (__cpp_lib_atomic_float): Define to indicate
	P0020R6 support.
	* include/std/memory (__cpp_lib_assume_aligned): Define to indicate
	P1007R3 support.
	* include/std/memory_resource (__cpp_lib_polymorphic_allocator):
	Define to indicate P0339R6 support.
	* include/std/string_view (__cpp_lib_starts_ends_with): Define to
	indicate P0457R2 support.
	* include/std/type_traits (__cpp_lib_is_nothrow_convertible): Define
	to indicate P0758R1 support.
	(__cpp_lib_remove_cvref): Define to indicate P0550R2 support.
	(__cpp_lib_type_identity): Define to indicate P0887R1 support.
	* include/std/version (__cpp_lib_atomic_float)
	(__cpp_lib_is_nothrow_convertible, __cpp_lib_remove_cvref)
	(__cpp_lib_type_identity, __cpp_lib_assume_aligned)
	(__cpp_lib_constexpr_memory, __cpp_lib_polymorphic_allocator)
	(__cpp_lib_shift, __cpp_lib_ssize, __cpp_lib_starts_ends_with)
	(__cpp_lib_to_address): Define.
	* testsuite/20_util/to_address/1_neg.cc: Adjust dg-error line number.

These macros were replaced by __cpp_lib_map_try_emplace and
__cpp_lib_unordered_map_try_emplace, because those names are more
descriptive. We've kept both old and new names so far, but I think we
can remove the old ones now.

	* include/bits/stl_map.h (__cpp_lib_map_insertion): Remove old
	macro.
	* include/bits/unordered_map.h (__cpp_lib_unordered_map_insertion):
	Likewise.
	* include/std/version (__cpp_lib_map_insertion)
	(__cpp_lib_unordered_map_insertion): Remove.

	* include/std/condition_variable (__cpp_lib_jthread): Remove
	redundant definition.
	* include/std/stop_token (__cpp_lib_jthread): Update macro value to
	indicate P1869R1 support.
	* include/std/version (__cpp_lib_jthread): Update value.
	* testsuite/30_threads/condition_variable_any/stop_token/1.cc: Check
	for updated macro value.
	* testsuite/30_threads/condition_variable_any/stop_token/2.cc:
	Likewise.
	* testsuite/30_threads/jthread/1.cc: Likewise.
	* testsuite/30_threads/jthread/2.cc: Likewise.
	* testsuite/30_threads/stop_token/1.cc: Likewise.
	* testsuite/30_threads/stop_token/2.cc: Likewise.

My fix for PR94549 broke constraints_satisfied_p in the case where the inherited
constructor decl points to an instantiation of a constructor template coming
from an instantiation of a class template.

This is because the DECL_TI_ARGS of the inherited constructor decl in this case
contains only the innermost level of template arguments (those for the
constructor template), but constraint satisfaction expects to have the full set
of template arguments.  This causes template argument substitution during
constraint satisfaction to fail in various ways.

On the other hand, the DECL_TI_ARGS of the DECL_INHERITED_CTOR is a full set of
template arguments but with the innermost level still in its dependent form,
which is the source of PR94549.  So if we could combine these two sets of
template arguments then we'd be golden.

This patch does just that, by effectively reverting the fix for PR94549 and
instead using add_outermost_template_args to combine the template arguments of
the inherited constructor decl with those of its DECL_INHERITED_CTOR.

gcc/cp/ChangeLog:

	PR c++/94719
	PR c++/94549
	* constraint.cc (satisfy_declaration_constraints): If the inherited
	constructor points to an instantiation of a constructor template,
	remember and use its attached template arguments.

gcc/testsuite/ChangeLog:

	PR c++/94719
	PR c++/94549
	* g++.dg/cpp2a/concepts-inherit-ctor9.C: New test.

This PR was initially accepts-invalid, but I think it's actually valid
C++20 code.  My reasoning is that in C++20 we no longer require the
declaration of operator== (#if-defed in the test), because C++20's
[temp.names]/2 says "A name is also considered to refer to a template
if it is an unqualified-id followed by a < and name lookup either finds
one or more functions or finds nothing." so when we're parsing

  constexpr friend bool operator==<T>(T lhs, const Foo& rhs);

we treat "operator==" as a template name, because name lookup of
"operator==" found nothing and we have an operator-function-id, which is
an unqualified-id, and it's followed by a <.  So the declaration isn't
needed to treat "operator==<T>" as a template-id.

	PR c++/93807
	* g++.dg/cpp2a/fn-template20.C: New test.

The following patch provides some further math library fallbacks.
fmaf can be implemented using fma if available, fma and fmal can use
x * y + z as fallback, it is not perfect, but e.g. glibc on various arches
has been using that as fallback for many years,
and copysign/copysignl/fabs/fabsl can be implemented using corresponding
__builtin_* if we make sure that gcc expands it inline instead of using
a library call (these days it is expanded inline on most targets).

2020-04-22  Jakub Jelinek  <jakub@redhat.com>

	PR libfortran/94694
	PR libfortran/94586
	* configure.ac: Add math func checks for fmaf, fma and fmal.  Add
	HAVE_INLINE_BUILTIN_COPYSIGN check.
	* c99_protos.h (copysign, fmaf, fma, fmal): Provide fallback
	prototypes.
	(HAVE_COPYSIGN, HAVE_FMAF, HAVE_FMA, HAVE_FMAL): Define if not
	defined and fallback version is provided.
	* intrinsics/c99_functions.c (copysign, fmaf, fma, fmal): Provide
	fallback implementations if possible
	* configure: Regenerated.
	* config.h.in: Regenerated.

	* math.m4 (GCC_CHECK_MATH_INLINE_BUILTIN_FALLBACK1,
	GCC_CHECK_MATH_INLINE_BUILTIN_FALLBACK2): New.

Since -mabi=ilp32 option is not compatible with large code model, Require
lp64 target for the following tests:
gcc.target/aarch64/pr63304_1.c
gcc.target/aarch64/pr70120-2.c
gcc.target/aarch64/pr94530.c
gcc.target/aarch64/reload-valid-spoff.c

2020-04-22  Duan bo  <duanbo3@huawei.com>

gcc/testsuite/
	PR testsuite/94712
	* gcc.target/aarch64/pr63304_1.c: Require lp64 target.
	* gcc.target/aarch64/pr70120-2.c: Likewise.
	* gcc.target/aarch64/pr94530.c: Likewise.
	* gcc.target/aarch64/reload-valid-spoff.c: Likewise.

As the two testcases for PR94678 show, -mgeneral-regs-only is handled
properly with SVE.  We should issue an error message instead of expanding
SVE builtin funtions when -mgeneral-regs-only option is specified.

The middle end should never try to use vector patterns when the vector
modes have been disabled by !have_regs_of_mode.  But it's still wrong
for the target to provide patterns that would inevitably lead to spill
failure due to lack of registers.  So we should also add check for
!TARGET_GENERAL_REGS_ONLY in TARGET_SVE and other SVE related macros.

2020-04-22  Felix Yang  <felix.yang@huawei.com>

gcc/
	PR target/94678
	* config/aarch64/aarch64.h (TARGET_SVE):
	Add && !TARGET_GENERAL_REGS_ONLY.
	(TARGET_SVE2): Add && TARGET_SVE.
	(TARGET_SVE2_AES, TARGET_SVE2_BITPERM, TARGET_SVE2_SHA3,
	TARGET_SVE2_SM4): Add && TARGET_SVE2.
	* config/aarch64/aarch64-sve-builtins.h
	(sve_switcher::m_old_general_regs_only): New member.
	* config/aarch64/aarch64-sve-builtins.cc (check_required_registers):
	New function.
	(reported_missing_registers_p): New variable.
	(check_required_extensions): Call check_required_registers before
	return if all required extenstions are present.
	(sve_switcher::sve_switcher): Save TARGET_GENERAL_REGS_ONLY in
	m_old_general_regs_only and clear MASK_GENERAL_REGS_ONLY in
	global_options.x_target_flags.
	(sve_switcher::~sve_switcher): Set MASK_GENERAL_REGS_ONLY in
	global_options.x_target_flags if m_old_general_regs_only is true.

gcc/testsuite/
	PR target/94678
	* gcc.target/aarch64/sve/acle/general/nosve_6.c: New test.

	* doc/extend.exi: Add "free" to list of other builtin functions
	supported by GCC.

For future architecture with prefix instructions, always use plq/pstq
rather than lq/stq for atomic load of quadword. Then we never have to
do the doubleword swap on little endian. Before this fix, -mno-pcrel
would generate lq with the doubleword swap (which was ok) and -mpcrel
would generate plq, also with the doubleword swap, which was wrong.

2020-04-20  Aaron Sawdey  <acsawdey@linux.ibm.com>

	PR target/94622
	* config/rs6000/sync.md (load_quadpti): Add attr "prefixed"
	if TARGET_PREFIXED.
	(store_quadpti): Ditto.
	(atomic_load<mode>): Do not swap doublewords if TARGET_PREFIXED as
	plq will be used and doesn't need it.
	(atomic_store<mode>): Ditto, for pstq.

	* doc/invoke.texi: Update flags turned on by -O3.

These warnings have nothing to do with virtual functions, so "override"
is inappropriate. The warnings are just talking about defining special
members, so let's say that.

	PR translation/94698
	* class.c (check_field_decls): Change "override" to "define" in
	-Weffc++ diagnostics.

2020-04-22  José Rui Faustino de Sousa  <jrfsousa@gmail.com>

	PR fortran/90350
	* simplify.c (simplify_bound): In the case of assumed-size arrays
	check if the reference is to a full array.

2020-04-22  José Rui Faustino de Sousa  <jrfsousa@gmail.com>

	PR fortran/90350
	* gfortran.dg/PR90350.f90: New test.

	PR c++/90448
	* g++.dg/cpp1y/lambda-generic-variadic20.C: New.

gcc/testsuite/ChangeLog:

	PR middle-end/94647
	* c-c++-common/Warray-bounds-2.c: Replace a large value harcoded
	in an expected warning with a pattern.

gcc/ChangeLog:

2020-04-21  Stefan Schulze Frielinghaus  <stefansf@linux.ibm.com>

	* config/s390/s390.md ("*<risbg_n>_ior_and_sr_ze<mode>"): Lift from SI
	mode to DSI. ("*trunc_sidi_and_subreg_ze<clobbercc_or_nocc>"): New
	insn pattern.

gcc/testsuite/ChangeLog:

2020-04-21  Stefan Schulze Frielinghaus  <stefansf@linux.ibm.com>

	* gcc.target/s390/addsub-signed-overflow-1.c: Fix options.
	* gcc.target/s390/addsub-signed-overflow-2.c: Fix options.
	* gcc.target/s390/bswap-1.c: Fix scan assembler regex.
	* gcc.target/s390/global-array-element-pic2.c: Fix scan assembler regex.
	* gcc.target/s390/load-relative-check.c: Fix options.
	* gcc.target/s390/morestack.c: Fix options.
	* gcc.target/s390/nobp-return-mem-z900.c: Temporarily silence this case.
	* gcc.target/s390/risbg-ll-1.c: Fix scan assembler regex.
	* gcc.target/s390/risbg-ll-2.c: Fix scan assembler regex.
	* gcc.target/s390/risbg-ll-3.c: Fix scan assembler regex.
	* gcc.target/s390/target-attribute/pr82012.c: Fix error message.

ia64 seems to be affected too, but the backend doesn't have any
-Wpsabi warnings and I'm not sure if we really need them for an (almost?)
dead target.

2020-04-22  Jakub Jelinek  <jakub@redhat.com>

	PR target/94706
	* config/ia64/ia64.c (hfa_element_mode): Ignore
	cxx17_empty_base_field_p fields.

As multiple targets are affected apparently, I believe at least
aarch64, arm, powerpc64le, s390{,x} and ia64,
I think we should have a middle-end predicate for this, so that if we need
to tweak it, we can do it in one spot.

2020-04-22  Jakub Jelinek  <jakub@redhat.com>

	PR target/94383
	* calls.h (cxx17_empty_base_field_p): Declare.
	* calls.c (cxx17_empty_base_field_p): Define.

Since arm_acle.h includes stdint.h, its use requires the presence of
the right gnu/stub-*.h, so make sure to include arm_acle.h when
checking the effective targets that generally imply that the testcase
will include it: arm_dsp, arm_crc, arm_coproc[1-4]

This makes several tests unsupported rather than fail.

2020-04-22  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* lib/target-supports.exp (check_effective_target_arm_dsp)
	(check_effective_target_arm_crc_ok_nocache)
	(check_effective_target_arm_coproc1_ok_nocache)
	(check_effective_target_arm_coproc2_ok_nocache)
	(check_effective_target_arm_coproc3_ok_nocache)
	(check_effective_target_arm_coproc4_ok_nocache): Include
	arm_acle.h.

Since arm_cde.h includes stdint.h, its use requires the presence of
the right gnu/stub-*.h, so make sure to include it when checking the
arm_v8*m_main_cde* effective targets, otherwise we can decide CDE is
supported while it's not really (all tests that use arm_v8m_main_cde*
also include arm_cde.h aynway).

Similarly for the effective targets that also require MVE.

This makes several tests unsupported rather than fail.

2020-04-22  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* lib/target-supports.exp (arm_v8m_main_cde, arm_v8m_main_cde_fp)
	(arm_v8_1m_main_cde_mve, arm_v8_1m_main_cde_mve_fp): Include
	arm_cde.h and arm_mve.h as ineeded.

Since arm_mve.h includes stdint.h, its use requires the presence of
the right gnu/stub-*.h, so make sure to include it when checking the
arm_v8_1m_mve_ok_nocache effective target, otherwise we can decide MVE
is supported while it's not really. This makes several tests
unsupported rather than fail.

2020-04-22  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* lib/target-supports.exp
	(check_effective_target_arm_v8_1m_mve_ok_nocache): Include
	arm_mve.h.

Several ARM/MVE tests can be compiled even if the toolchain does not
support -mfloat-abi=hard (softfp is OK).

Use dg-add-options arm_v8_1m_mve or arm_v8_1m_mve_fp instead of using
dg-additional-options.

2020-04-22  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* gcc.target/arm/mve/intrinsics/mve_vector_float.c: Use
	arm_v8_1m_mve_fp.
	* gcc.target/arm/mve/intrinsics/mve_vector_float1.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_vector_float2.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_vector_int.c: Use
	arm_v8_1m_mve.
	* gcc.target/arm/mve/intrinsics/mve_vector_int1.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_vector_int2.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_vector_uint.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_vector_uint1.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_vector_uint2.c: Likewise.

This test can pass with a hard-float toolchain, provided we don't
force -mfloat-abi=softfp.

This patch removes this useless option, as well as -save-temps which
is implied by arm_v8_1m_mve_fp.

2020-04-22  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* gcc.target/arm/mve/intrinsics/mve_move_gpr_to_gpr.c: Remove
	useless options.

Some MVE tests explicitly test a -mfloat-abi=hard option, but we need
to check that the toolchain actually supports it (which may not be the
case for arm-linux-gnueabi* targets). We can thus remove the related
dg-skip directives.

We also make use of dg-add-options arm_v8_1m_mve_fp and arm_v8_1m_mve
instead of duplicating the corresponding options in
dg-additional-options where we keep only -mfloat-abi to override the
option selected by arm_v8_1m_mve_fp.

2020-04-22  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* gcc.target/arm/mve/intrinsics/mve_fp_fpu1.c: Use arm_hard_ok
	effective target and arm_v8_1m_mve_fp options.
	* gcc.target/arm/mve/intrinsics/mve_fp_fpu2.c: Use arm_softfp_ok
	effective target and arm_v8_1m_mve_fp options.
	* gcc.target/arm/mve/intrinsics/mve_fpu1.c: Use arm_hard_ok
	effective target and arm_v8_1m_mve options.
	* gcc.target/arm/mve/intrinsics/mve_fpu2.c: Use arm_softfp_ok
	effective target and arm_v8_1m_mve options.

For arm-linux-gnueabi* targets, a toolchain cannot support the
float-abi opposite to the one it has been configured for: since glibc
does not support such multilibs, we end up lacking gnu/stubs-*.h when
including stdint.h for instance.

This patch introduces two new effective targets to detect whether we
can compile tests with -mfloat-abi=softfp or -mfloat-abi=hard.

This enables to make such tests unsupported rather than fail.

2020-04-22  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* lib/target-supports.exp (arm_softfp_ok): New effective target.
	(arm_hard_ok): Likewise.

	gcc/
	* doc/sourcebuild.texi (arm_softfp_ok, arm_hard_ok): Document.

This patch adds initial -mcpu support for the Arm Cortex-M55 CPU.
This CPU is an Armv8.1-M Mainline CPU supporting MVE.
An option to disable floating-point (and MVE) is provided with the +nofp.
For GCC 11 I'd like to add further fine-grained options to enable integer-only MVE
but that needs a bit more elaborate surgery in arm-cpus.in that I don't want to do
in GCC 10 at this stage.

As this CPU is not supported in gas and I don't want to couple GCC 10 to the very
latest binutils anyway, this CPU emits the cpu string in the assembly file as a build attribute
rather than a .cpu directive, thus sparing us the need to support .cpu cortex-m55 in gas.
The .cpu directive in gas isn't used for anything besides setting the Tag_CPU_name
build attribute anyway (which itself is not used by any tools I'm aware of).
All the architecture information used for target detection is already emitted using .arch_extension
directives and similar.

Bootstrapped and tested on arm-none-linux-gnueabihf. Also tested on arm-none-eabi.

2020-04-22  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
            Andre Vieira  <andre.simoesdiasvieira@arm.com>
            Mihail Ionescu  <mihail.ionescu@arm.com>

	* config/arm/arm.c (arm_file_start): Handle isa_bit_quirk_no_asmcpu.
	* config/arm/arm-cpus.in (quirk_no_asmcpu): Define.
	(ALL_QUIRKS): Add quirk_no_asmcpu.
	(cortex-m55): Define new cpu.
	* config/arm/arm-tables.opt: Regenerate.
	* config/arm/arm-tune.md: Likewise.
	* doc/invoke.texi (Arm Options): Document -mcpu=cortex-m55.

While '!$' with -fopenmp unsets too often load_line's seen_comment flag,
this only affects <tab> warnings; for trunction warnings, gfc_next_char_literal
re-handles the directives correctly.  In terms of missed warnings, a directive
that is completely in the truncated part is not diagnosted (as it starts
with a '!').

        PR fortran/94709
        * scanner.c (load_line): In fixed form, also treat 'C' as comment and
        'D'/'d' only with -fd-lines-as-comments. Treat '!$' with -fopenmp,
        '!$acc' with -fopenacc and '!GCC$' as non-comment to permit <tab>
        and truncation warnings.

        PR fortran/94709
        * gfortran.dg/gomp/warn_truncated.f: New.
        * gfortran.dg/gomp/warn_truncated.f90: New.

This is really PR94683 part 2, handling the case in which the vector is
an identity and so doesn't need a VEC_PERM_EXPR.  I should have realised
at the time that the other arm of the "if" would need the same fix.

2020-04-22  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	PR tree-optimization/94700
	* tree-ssa-forwprop.c (simplify_vector_constructor): When processing
	an identity constructor, use a VIEW_CONVERT_EXPR to handle mixtures
	of similarly-structured but distinct vector types.

gcc/testsuite/
	PR tree-optimization/94700
	* gcc.target/aarch64/sve/acle/general/pr94700.c: New test.

Try to make sure that we have consistent naming for the tests
before first release.

gcc/testsuite/ChangeLog:

2020-04-22 Iain Sandoe <iain@sandoe.co.uk>

	* g++.dg/coroutines/torture/local-var-0.C: Rename to...
	* g++.dg/coroutines/torture/local-var-00-const.C: ...this.
	* g++.dg/coroutines/torture/local-var-1.C: Rename to...
	* g++.dg/coroutines/torture/local-var-01-single.C: ...this.
	* g++.dg/coroutines/torture/local-var-2.C: Rename to...
	* g++.dg/coroutines/torture/local-var-02-conditional.C: ...this.
	* g++.dg/coroutines/torture/local-var-3.C: Rename to...
	* g++.dg/coroutines/torture/local-var-03-with-awaits.C: ...this.
	* g++.dg/coroutines/torture/local-var-4.C: Rename to...
	* g++.dg/coroutines/torture/local-var-04-hiding-nested-scopes.C: this.
	* g++.dg/coroutines/torture/local-var-5-awaitable.C: Rename to...
	* g++.dg/coroutines/torture/local-var-05-awaitable.C: ...this.

As reported in the PR, per [dcl.fct.def.coroutine]/4 we should
be passing a reference to the object to the promise parameter
preview, and we are currently passing a pointer (this).  Amend to
pass the reference.

gcc/cp/ChangeLog:

2020-04-22  Iain Sandoe  <iain@sandoe.co.uk>

	PR c++/94682
	* coroutines.cc (struct param_info): Add a field to note that
	the param is 'this'.
	(morph_fn_to_coro): Convert this to a reference before using it
	in the promise parameter preview.

gcc/testsuite/ChangeLog:

2020-04-22  Iain Sandoe  <iain@sandoe.co.uk>

	PR c++/94682
	* g++.dg/coroutines/pr94682-preview-this.C: New test.

ChangeLog:

2020-04-22  Stefan Schulze Frielinghaus  <stefansf@linux.ibm.com>

	* MAINTAINERS (Write After Approval): add myself

Some tests use --save-temps, but schedule-cleanups strictly matches
-save-temps, so we leave many temporary files after validation.
Instead of fixing every offending testcase, it's simpler and
future-proof to make schedule-cleanups handle both --save-temps and
-save-temps.

2020-04-22  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* lib/gcc-dg.exp (schedule-cleanups): Accept --save-temps.

While instantiating test(Plot) we partially instantiate the generic lambda.
We look at forward<T>(rest)... and see that it's just replacing parameter
packs with new parameter packs and tries to do a direct substitution.  But
because register_parameter_specializations had built up a
NONTYPE_ARGUMENT_PACK around the new parameter pack, the substitution
failed.  So let's not wrap it that way.

gcc/cp/ChangeLog
2020-04-22  Jason Merrill  <jason@redhat.com>

	PR c++/94546
	* pt.c (register_parameter_specializations): If the instantiation is
	still a parameter pack, don't wrap it in a NONTYPE_ARGUMENT_PACK.
	(tsubst_pack_expansion, tsubst_expr): Adjust.

The change committed to GCC 9 to allow string literals as template arguments
caused the compiler to prune away, and thus miss diagnosing, conversion from
nullptr to int in an array initializer.  After looking at various approaches
to improving the pruning, we realized that the only place the pruning is
necessary is in the mangler.

gcc/cp/ChangeLog
2020-04-22  Martin Sebor  <msebor@redhat.com>
	    Jason Merrill  <jason@redhat.com>

	PR c++/94510
	* decl.c (reshape_init_array_1): Avoid stripping redundant trailing
	zero initializers...
	* mangle.c (write_expression): ...and handle them here even for
	pointers to members by calling zero_init_expr_p.
	* cp-tree.h (zero_init_expr_p): Declare.
	* tree.c (zero_init_expr_p): Define.
	(type_initializer_zero_p): Remove.
	* pt.c (tparm_obj_values): New hash_map.
	(get_template_parm_object): Store to it.
	(tparm_object_argument): New.

gcc/testsuite/ChangeLog
2020-04-22  Martin Sebor  <msebor@redhat.com>

	PR c++/94510
	* g++.dg/init/array58.C: New test.
	* g++.dg/init/array59.C: New test.
	* g++.dg/cpp2a/nontype-class34.C: New test.
	* g++.dg/cpp2a/nontype-class35.C: New test.

	* testsuite/21_strings/basic_string/erasure.cc: Check for updated
	value of __cpp_lib_erase_if.
	* testsuite/23_containers/deque/erasure.cc: Likewise.
	* testsuite/23_containers/forward_list/erasure.cc: Likewise.
	* testsuite/23_containers/list/erasure.cc: Likewise.
	* testsuite/23_containers/map/erasure.cc: Likewise.
	* testsuite/23_containers/set/erasure.cc: Likewise.
	* testsuite/23_containers/unordered_map/erasure.cc: Likewise.
	* testsuite/23_containers/unordered_set/erasure.cc: Likewise.
	* testsuite/23_containers/vector/erasure.cc: Likewise.

This updates diagnose_valid_expression to mirror the convert_to_void check added
to tsubst_valid_expression_requirement by r10-7554.

gcc/cp/ChangeLog:

	PR c++/67825
	* constraint.cc (diagnose_valid_expression): Check convert_to_void here
	as well as in tsubst_valid_expression_requirement.

gcc/testsuite/ChangeLog:

	PR c++/67825
	* g++.dg/concepts/diagnostic10.C: New test.
	* g++.dg/cpp2a/concepts-pr67178.C: Adjust dg-message.