Some more C++20 changes from P1614R2, "The Mothership has Landed".

	* include/bits/stl_queue.h (queue): Define operator<=> for C++20.
	* include/bits/stl_stack.h (stack): Likewise.
	* testsuite/23_containers/queue/cmp_c++20.cc: New test.
	* testsuite/23_containers/stack/cmp_c++20.cc: New test.

Some more C++20 changes from P1614R2, "The Mothership has Landed".

	* include/bits/unordered_map.h (unordered_map, unordered_multimap):
	Remove redundant operator!= for C++20.
	* include/bits/unordered_set.h (unordered_set, unordered_multiset):
	Likewise.
	* include/debug/unordered_map (unordered_map, unordered_multimap):
	Likewise.
	* include/debug/unordered_set (unordered_set, unordered_multiset):
	Likewise.

This appears to be a copy&paste error, which cppcheck diagnoses.

	PR other/94629
	* include/debug/formatter.h (_Error_formatter::_Parameter): Fix
	redundant assignment in constructor.

AIX does not support DWARF5 sections.
-fcompare-debug causes gratuitous testcase failures on AIX.

2020-04-19  David Edelsohn  <dje.gcc@gmail.com>

        * g++.dg/debug/dwarf2/pr85550.C: Skip AIX.
        * g++.dg/debug/pr94272.C: Skip AIX.
        * g++.dg/debug/pr94281.C: Skip AIX.
        * g++.dg/debug/pr94323.C: Skip AIX.

std.array.Appender and RefAppender: use .opSlice() instead of data()

Previously, Appender.data() was used to extract a slice of the Appender's array.
Now use the [] slice operator instead.  The same goes for RefAppender.

Fixes: PR d/94455

Reviewed-on: https://github.com/dlang/phobos/pull/7450

Fixes hasLength unittest to pass on X32.

References: PR d/94609

Reviewed-on: https://github.com/dlang/phobos/pull/7448

Initializes the VectorArrayExp::size field with the correct value.

Fixes: PR d/94652

Reviewed-on: https://github.com/dlang/dmd/pull/11046

Initializes ncost before use, which was caught by valgrind.

Fixes: PR d/94653

Reviewed-on: https://github.com/dlang/dmd/pull/11045

According to "Intel 64 and IA32 Arch SDM, Vol. 3:

"Because SIMD floating-point exceptions are precise and occur immediately,
the situation does not arise where an x87 FPU instruction, a WAIT/FWAIT
instruction, or another SSE/SSE2/SSE3 instruction will catch a pending
unmasked SIMD floating-point exception."

Remove unneeded assignments to volatile memory.

libgcc/ChangeLog:

	* config/i386/sfp-exceptions.c (__sfp_handle_exceptions) [__SSE_MATH__]:
	Remove unneeded assignments to volatile memory.

libatomic/ChangeLog:

	* config/x86/fenv.c (__atomic_feraiseexcept) [__SSE_MATH__]:
	Remove unneeded assignments to volatile memory.

libgfortran/ChangeLog:

	* config/fpu-387.h (local_feraiseexcept) [__SSE_MATH__]:
	Remove unneeded assignments to volatile memory.

While the coroutines implementation, and most of the coroutines
tests, will operate with C++14 or newer, these tests require
facilities introduced in C++17.  Add the target requirement.

gcc/testsuite/

2020-04-19  Iain Sandoe  <iain@sandoe.co.uk>

	* g++.dg/coroutines/torture/co-await-17-capture-comp-ref.C: Require
	C++17.
	* g++.dg/coroutines/torture/co-ret-15-default-return_void.C: Likewise.

2020-04-19  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/94347
	* gfortran.dg/char_pointer_init_1.f90: New test.

2020-04-19  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/57129
	* gfortran.dg/subroutine_as_type.f90: New test.

Returning &gfc_bad_expr when simplifying bounds after a divisin by zero
happened results in the division by zero error actually reaching the user.

2020-04-19  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/93500
	* resolve.c (resolve_operator): If both operands are
	NULL, return false.
	* simplify.c (simplify_bound): If a division by zero
	was seen during bound simplification, free the
	corresponcing expression and return &gfc_bad_expr.

2020-04-19  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/93500
	* arith_divide_3.f90: New test.

Similarly to inline asm, :: (or any other number of consecutive colons) can
appear in ObjC @selector argument and with the introduction of CPP_SCOPE
into the C FE, we need to trat CPP_SCOPE as two CPP_COLON tokens.
The C++ FE does that already that way.

2020-04-19  Jakub Jelinek  <jakub@redhat.com>

	PR objc/94637
	* c-parser.c (c_parser_objc_selector_arg): Handle CPP_SCOPE like
	two CPP_COLON tokens.

	* objc.dg/pr94637.m: New test.

Patch fixes test failure seen on X32 where a nested struct was passed in
registers, rather than via invisible reference.  Now, all non-POD
structs are passed by invisible reference, not just those with a
user-defined copy constructor/destructor.

gcc/d/ChangeLog:

	PR d/94609
	* d-codegen.cc (argument_reference_p): Don't check TREE_ADDRESSABLE.
	(type_passed_as): Build reference type if TREE_ADDRESSABLE.
	* d-convert.cc (convert_for_argument): Build explicit TARGET_EXPR if
	needed for arguments passed by invisible reference.
	* types.cc (TypeVisitor::visit (TypeStruct *)): Mark all structs that
	are not POD as TREE_ADDRESSABLE.

The intended purpose of the option is both for targets that don't
support phobos yet, and for gdc itself to support bootstrapping itself
as a self-hosted D compiler.

The libphobos testsuite has been updated to only add libphobos to the
search paths if it's being built.  A new D2 testsuite directive
RUNNABLE_PHOBOS_TEST has also been patched in to disable some runnable
tests that have phobos dependencies, of which is a temporary measure
until upstream DMD fixes or removes these tests entirely.

gcc/testsuite/ChangeLog:

	* lib/gdc-utils.exp (gdc-convert-test): Add dg-skip-if for tests that
	depending on the phobos standard library.

libphobos/ChangeLog:

	* configure: Regenerate.
	* configure.ac: Add --with-libphobos-druntime-only option and the
	conditional ENABLE_LIBDRUNTIME_ONLY.
	* configure.tgt: Define LIBDRUNTIME_ONLY.
	* src/Makefile.am: Add phobos sources if not ENABLE_LIBDRUNTIME_ONLY.
	* src/Makefile.in: Regenerate.
	* testsuite/testsuite_flags.in: Add phobos path if compiling phobos.

	PR debug/94439
	* regrename.c (check_new_reg_p): Ignore DEBUG_INSNs when walking
	the chain.

	PR debug/94439
	* gcc.dg/torture/pr94439.c: New test.

The current check_effective_target_d_runtime procedure returns false if
the target is built without any core runtime library for D being
available (--disable-libphobos).  This additional procedure is for
targets where the core runtime library exists, but without the higher
level standard library.

gcc/ChangeLog:

	* doc/sourcebuild.texi (Effective-Target Keywords, Environment
	attributes): Document d_runtime_has_std_library.

gcc/testsuite/ChangeLog:

	* gdc.dg/link.d: Use d_runtime_has_std_library effective target.
	* gdc.dg/runnable.d: Move phobos tests to...
	* gdc.dg/runnable2.d: ...here.  New test.
	* lib/target-supports.exp
	(check_effective_target_d_runtime_has_std_library): New.

libphobos/ChangeLog:

	* testsuite/libphobos.phobos/phobos.exp: Skip if effective target is
	not d_runtime_has_std_library.
	* testsuite/libphobos.phobos_shared/phobos_shared.exp: Likewise.

In the testcase below, during specialization of c<int>::d, we build two
identical specializations of the parameter type b<decltype(e)::k> -- one when
substituting into c<int>::d's TYPE_ARG_TYPES and another when substituting into
c<int>::d's DECL_ARGUMENTS.

We don't reuse the first specialization the second time around as a consequence
of the fix for PR c++/56247 which made PARM_DECLs always compare different from
one another during spec_hasher::equal.  As a result, when looking up existing
specializations of 'b', spec_hasher::equal considers the template argument
decltype(e')::k to be different from decltype(e'')::k, where e' and e'' are the
result of two calls to tsubst_copy on the PARM_DECL e.

Since the two specializations are considered different due to the mentioned fix,
their TYPE_CANONICAL points to themselves even though they are otherwise
identical types, and this triggers an ICE in maybe_rebuild_function_decl_type
when comparing the TYPE_ARG_TYPES of c<int>::d to its DECL_ARGUMENTS.

This patch fixes this issue at the spec_hasher::equal level by ignoring the
'comparing_specializations' flag in cp_tree_equal whenever the DECL_CONTEXTs of
the two parameters are identical.  This seems to be a sufficient condition to be
able to correctly compare PARM_DECLs structurally.  (This also subsumes the
CONSTRAINT_VAR_P check since constraint variables all have empty, and therefore
identical, DECL_CONTEXTs.)

gcc/cp/ChangeLog:

	PR c++/94632
	* tree.c (cp_tree_equal) <case PARM_DECL>: Ignore
	comparing_specializations if the parameters' contexts are identical.

gcc/testsuite/ChangeLog:

	PR c++/94632
	* g++.dg/template/canon-type-14.C: New test.

When updating an auto return type of an abbreviated function template in
splice_late_return_type, we should also propagate PLACEHOLDER_TYPE_CONSTRAINTS
(and cv-qualifiers) of the original auto node.

gcc/cp/ChangeLog:

	PR c++/92187
	* pt.c (splice_late_return_type): Propagate cv-qualifiers and
	PLACEHOLDER_TYPE_CONSTRAINTS from the original auto node to the new one.

gcc/testsuite/ChangeLog:

	PR c++/92187
	* g++.dg/concepts/abbrev5.C: New test.
	* g++.dg/concepts/abbrev6.C: New test.

Some more C++20 changes from P1614R2, "The Mothership has Landed".

	* include/std/chrono (duration, time_point): Define operator<=> and
	remove redundant operator!= for C++20.
	* testsuite/20_util/duration/comparison_operators/three_way.cc: New
	test.
	* testsuite/20_util/time_point/comparison_operators/three_way.cc: New
	test.

In C++20 the rebind and const_reference members of std::allocator are
gone, so this testsuite utility stopped working, causing
ext/pb_ds/regression/priority_queue_rand_debug.cc to FAIL.

	* testsuite/util/native_type/native_priority_queue.hpp: Use
	allocator_traits to rebind allocator.

Some more C++20 changes from P1614R2, "The Mothership has Landed".

This implements <=> for sequence containers (and the __normal_iterator
and _Pointer_adapter class templates).

	* include/bits/forward_list.h (forward_list): Define operator<=> and
	remove redundant comparison operators for C++20.
	* include/bits/stl_bvector.h (vector<bool, Alloc>): Likewise.
	* include/bits/stl_deque.h (deque): Likewise.
	* include/bits/stl_iterator.h (__normal_iterator): Likewise.
	* include/bits/stl_list.h (list): Likewise.
	* include/bits/stl_vector.h (vector): Likewise.
	* include/debug/deque (__gnu_debug::deque): Likewise.
	* include/debug/forward_list (__gnu_debug::forward_list): Likewise.
	* include/debug/list (__gnu_debug::list): Likewise.
	* include/debug/safe_iterator.h (__gnu_debug::_Safe_iterator):
	Likewise.
	* include/debug/vector (__gnu_debug::vector): Likewise.
	* include/ext/pointer.h (__gnu_cxx::_Pointer_adapter): Define
	operator<=> for C++20.
	* testsuite/23_containers/deque/operators/cmp_c++20.cc: New test.
	* testsuite/23_containers/forward_list/cmp_c++20.cc: New test.
	* testsuite/23_containers/list/cmp_c++20.cc: New test.
	* testsuite/23_containers/vector/bool/cmp_c++20.cc: New test.
	* testsuite/23_containers/vector/cmp_c++20.cc: New test.

This time instead of having a NOP copy insn that we can completely ignore and
ultimately remove, we have a NOP set within a multi-set PARALLEL.  It triggers,
the same failure when the source of such a set is a hard register for the same
reasons as we've already noted in the BZ and patches-to-date.

For prior cases we've been able to mark the insn as a nop set and ignore it for
the rest of cse_insn, ultimately removing it.  That's not really an option here
as there are other sets that we have to preserve.

We might be able to fix this instance by splitting the multi-set insn, but I'm
not keen to introduce splitting into cse.  Furthermore, the target may not be
able to split the insn.  So I considered this is non-starter.

What I finally settled on was to use the existing do_not_record machinery to
ignore the nop set within the parallel (and only that set within the parallel).

One might argue that we should always ignore a REG_UNUSED set.  But I rejected
that idea -- we could have cse-able divmod insns where the first had a
REG_UNUSED note for a destination, but the second did not.

One might also argue that we could have a nop set without a REG_UNUSED in a
multi-set parallel and thus we could trigger yet another insert_regs ICE at
some point.  I tend to think this is a possibility.  If we see this happen,
we'll have to revisit.

	PR rtl-optimization/90275
	* cse.c (cse_insn): Avoid recording nop sets in multi-set parallels
	when the destination has a REG_UNUSED note.

In this PR, we're ICEing on a use of an 'int... a' template parameter pack as
part of the variadic lambda init-capture [...z=a].

The unexpected thing about this variadic init-capture is that it is not
type-dependent, and so the call to do_auto_deduction from
lambda_capture_field_type actually resolves its type to 'int' instead of exiting
early like it does for a type-dependent variadic initializer.  This later
confuses add_capture which, according to one of its comments, assumes that
'type' is always 'auto' for a variadic init-capture.

The simplest fix (and the approach that this patch takes) seems to be to avoid
doing auto deduction in lambda_capture_field_type when the initializer uses
parameter packs, so that we always return 'auto' even in the non-type-dependent
case.

gcc/cp/ChangeLog:

	PR c++/94483
	* lambda.c (lambda_capture_field_type): Avoid doing auto deduction if
	the explicit initializer has parameter packs.

gcc/testsuite/ChangeLog:

	PR c++/94483
	* g++.dg/cpp2a/lambda-pack-init5.C: New test.

In the testcase for this PR, we try to parse the statement

  A(value<0>());

first tentatively as a declaration (with a parenthesized declarator), and during
this tentative parse we end up issuing a hard error from
cp_parser_check_template_parameters about its invalidness as a declaration.

Rather than issuing a hard error, it seems we should instead simulate an error
since we're parsing tentatively.  This would then allow cp_parser_statement to
recover and successfully parse the statement as an expression-statement instead.

gcc/cp/ChangeLog:

	PR c++/88754
	* parser.c (cp_parser_check_template_parameters): Before issuing a hard
	error, first try simulating an error instead.

gcc/testsuite/ChangeLog:

	PR c++/88754
	* g++.dg/parse/ambig10.C: New test.

The attached patch fixes an ICE on invalid: When the return type of
a function was misdeclared with a wrong rank, we issued a warning,
but not an error (unless with -pedantic); later on, an ICE ensued.

Nothing good can come from wrongly declaring a function type
(considering the ABI), so I changed that into a hard error.

2020-04-17  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/94090
	* gfortran.dg (gfc_compare_interfaces): Add
	optional argument bad_result_characteristics.
	* interface.c (gfc_check_result_characteristics): Fix
	whitespace.
	(gfc_compare_interfaces): Handle new argument; return
	true if function return values are wrong.
	* resolve.c (resolve_global_procedure): Hard error if
	the return value of a function is wrong.

2020-04-17  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/94090
	* gfortran.dg/interface_46.f90: New test.

	PR middle-end/94635
	* gimplify.c (gimplify_scan_omp_clauses): Turn MAP_TO_PSET to
	MAP_DELETE.

	PR middle-end/94635
	* testsuite/libgomp.fortran/target-enter-data-2.F90: New.

Some more C++20 changes from P1614R2, "The Mothership has Landed".

This adds three-way comparison support to std::char_traits,
std::basic_string, std::basic_string_view, and std::sub_match.

	* include/bits/basic_string.h (basic_string): Define operator<=> and
	remove redundant comparison operators for C++20.
	* include/bits/char_traits.h (__gnu_cxx::char_traits, char_traits):
	Add comparison_category members.
	(__detail::__char_traits_cmp_cat): New helper to get comparison
	category from char traits class.
	* include/bits/regex.h (regex_traits::_RegexMask::operator!=): Do not
	define for C++20.
	(sub_match): Define operator<=> and remove redundant comparison
	operators for C++20.
	(match_results): Remove redundant operator!= for C++20.
	* include/std/string_view (basic_string_view): Define operator<=> and
	remove redundant comparison operators for C++20.
	* testsuite/21_strings/basic_string/operators/char/cmp_c++20.cc: New
	test.
	* testsuite/21_strings/basic_string/operators/wchar_t/cmp_c++20.cc:
	New test.
	* testsuite/21_strings/basic_string_view/operations/copy/char/
	constexpr.cc: Initialize variable.
	* testsuite/21_strings/basic_string_view/operations/copy/wchar_t/
	constexpr.cc: Likewise.
	* testsuite/21_strings/basic_string_view/operators/char/2.cc: Add
	dg-do directive and remove comments showing incorrect signatures.
	* testsuite/21_strings/basic_string_view/operators/wchar_t/2.cc:
	Likewise.
	* testsuite/21_strings/basic_string_view/operators/char/cmp_c++20.cc:
	New test.
	* testsuite/21_strings/basic_string_view/operators/wchar_t/cmp_c++20.cc:
	New test.
	* testsuite/28_regex/sub_match/compare_c++20.cc: New test.

We were seeing performance regressions on 256-bit SVE with code like:

  for (int i = 0; i < count; ++i)
  #pragma GCC unroll 128
    for (int j = 0; j < 128; ++j)
      *dst++ = 1;

(derived from lmbench).

For 128-bit SVE, it's clearly better to use Advanced SIMD STPs here,
since they can store 256 bits at a time.  We already do this for
-msve-vector-bits=128 because in that case Advanced SIMD comes first
in autovectorize_vector_modes.

If we handled full-loop predication well for this kind of loop,
the choice between Advanced SIMD and 256-bit SVE would be mostly
a wash, since both of them could store 256 bits at a time.  However,
SVE would still have the extra prologue overhead of setting up the
predicate, so Advanced SIMD would still be the natural choice.

As things stand though, we don't handle full-loop predication well
for this kind of loop, so the 256-bit SVE code is significantly worse.
Something to fix for GCC 11 (hopefully).  However, even though we
account for the overhead of predication in the cost model, the SVE
version (wrongly) appeared to need half the number of stores.
That was enough to drown out the predication overhead and meant
that we'd pick the SVE code over the Advanced SIMD code.

512-bit SVE has a clear advantage over Advanced SIMD, so we should
continue using SVE there.

This patch tries to account for this in the cost model.  It's a bit
of a compromise; see the comment in the patch for more details.

2020-04-17  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/aarch64/aarch64.c (aarch64_advsimd_ldp_stp_p): New function.
	(aarch64_sve_adjust_stmt_cost): Add a vectype parameter.  Double the
	cost of load and store insns if one loop iteration has enough scalar
	elements to use an Advanced SIMD LDP or STP.
	(aarch64_add_stmt_cost): Update call accordingly.

gcc/testsuite/
	* gcc.target/aarch64/sve/cost_model_2.c: New test.
	* gcc.target/aarch64/sve/cost_model_3.c: Likewise.
	* gcc.target/aarch64/sve/cost_model_4.c: Likewise.
	* gcc.target/aarch64/sve/cost_model_5.c: Likewise.
	* gcc.target/aarch64/sve/cost_model_6.c: Likewise.
	* gcc.target/aarch64/sve/cost_model_7.c: Likewise.

This change fixes two obvious redundant assignments reported by cppcheck:
trunk.git/gcc/c/c-parser.c:16969:2: style: Variable 'data.clauses' is reassigned a value before the old one has been used. [redundantAssignment]
trunk.git/gcc/cp/call.c:5116:9: style: Variable 'arg2' is reassigned a value before the old one has been used. [redundantAssignment]

2020-04-17  Jakub Jelinek  <jakub@redhat.com>

	PR other/94629
	* c-parser.c (c_parser_oacc_routine): Remove redundant assignment
	to data.clauses.

	* call.c (build_conditional_expr_1): Remove redundant assignment to
	arg2.

As the testcase shows, there are unfortunately more problematic cases
in *testqi_ext_3 if the mode is not CCZmode, because the sign flag might
not behave the same between the insn with zero_extract and what we split it
into.

The previous fix to the insn condition was because *testdi_1 for mask with
upper 32-bits clear and bit 31 set is implemented using SImode test and thus
SF is set depending on that bit 31 rather than on always cleared.

But we can have other cases.  On the zero_extract (which has <MODE>mode),
we can have either the pos + len == precision of <MODE>mode, or
pos + len < precision of <MODE>mode cases.  The former one copies the most
significant bit into SF, the latter will have SF always cleared.

For the former case, either it is a zero_extract from a larger mode, but
then when we perform test in that larger mode, SF will be always clear and
thus mismatch from the zero_extract case (so we need to enforce CCZmode),
or it will be a zero_extract from same mode with pos 0 and len equal to
mode precision, such zero_extracts should have been really simplified
into their first operand.

For the latter case, when SF is always clear on the define_insn with
zero_extract, we need to split into something that doesn't sometimes set
SF, i.e. it has to be a test with mask that doesn't have the most
significant bit set.  In some cases it can be achieved through using test
in a wider mode (e.g. in the testcase, there is
(zero_extract:SI (reg:HI) (const_int 13) (const_int 3))
which will always set SF to 0, but we split it into
(and:HI (reg:HI) (const_int -8))
which will copy the MSB of (reg:HI) into SF, but we can do:
(and:SI (subreg:SI (reg:HI) 0) (const_int 0xfff8))
which will keep SF always cleared), but there are various cases where we
can't (when already using DImode, or when SImode and we'd turned it into
the problematic *testdi_1 implemented using SImode test, or when
the val operand is a MEM (we don't want to read from memory more than
the user originally wanted), paradoxical subreg of MEM could be problematic
too if we through the narrowing end up with a MEM).

So, the patch attempts to require CCZmode (and not CCNOmode) if it can't
really ensure the SF will have same meaning between the define_insn and what
we split it into, and if we decide we allow CCNOmode, it needs to avoid
performing narrowing and/or widen if pos + len would indicate we'd have MSB
set in the mask.

2020-04-17  Jakub Jelinek  <jakub@redhat.com>
	    Jeff Law  <law@redhat.com>

	PR target/94567
	* config/i386/i386.md (*testqi_ext_3): Use CCZmode rather than
	CCNOmode in ix86_match_ccmode if len is equal to <MODE>mode precision,
	or pos + len >= 32, or pos + len is equal to operands[2] precision
	and operands[2] is not a register operand.  During splitting perform
	SImode AND if operands[0] doesn't have CCZmode and pos + len is
	equal to mode precision.

	* gcc.c-torture/execute/pr94567.c: New test.

Co-Authored-By: Jeff Law <law@redhat.com>

	PR c++/94608
	* g++.dg/lto/pr83720_0.C: Add fn def to avoid warning on arm ABI.

	PR lto/94612
	* lto-common.c: Initialize file_data->lto_section_header
	before lto_mode_identity_table call.  It is needed because
	it decompresses a LTO section.

2020-04-17  Richard Biener  <rguenther@suse.de>

	PR other/94629
	* cgraphclones.c (cgraph_node::create_clone): Remove duplicate
	initialization.
	* dwarf2out.c (dw_val_equal_p): Fix pasto in
	dw_val_class_vms_delta comparison.
	* optabs.c (expand_binop_directly): Fix pasto in commutation
	check.
	* tree-ssa-sccvn.c (vn_reference_lookup_pieces): Fix pasto in
	initialization.

delete_insn_and_edges calls purge_dead_edges whenever deleting the last insn
in a bb, whatever it is.  If it called it only for mandatory last insns
in the basic block (that may not be followed by DEBUG_INSNs, dunno if that
is control_flow_insn_p or something more complex), that wouldn't be a
problem, but as it calls it on any last insn and can actually do something
in the bb, if such an insn is followed by one more more DEBUG_INSNs and
nothing else in the same bb, we don't call purge_dead_edges with -g and do
call it with -g0.

On the testcase, there are two reg-to-reg moves with REG_EH_REGION notes
(previously memory accesses but simplified and yet not optimized), and the
second is followed by DEBUG_INSNs; the second move is delete_insn_and_edges
and after removing it, for -g0 purge_dead_edges removes the REG_EH_REGION
from the now last insn in the bb (the first reg-to-reg move), while
for -g it isn't called and things diverge from that quickly on.

Fixed by calling purdge_dead_edges even if we remove the last real insn
followed only by DEBUG_INSNs in the same bb.

2020-04-17  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/94618
	* cfgrtl.c (delete_insn_and_edges): Set purge not just when
	insn is the BB_END of its block, but also when it is only followed
	by DEBUG_INSNs in its block.

	* g++.dg/opt/pr94618.C: New test.