[Bug middle-end/95021] New: [10/11 Regression] Bogus -Wclobbered warning

[Bug middle-end/95021] New: [10/11 Regression] Bogus -Wclobbered warning

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

            Bug ID: 95021
           Summary: [10/11 Regression] Bogus -Wclobbered warning
           Product: gcc
           Version: 10.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
  Target Milestone: ---

On Linux/x86-64, GCC 10 and 11 give

[hjl@gnu-skx-1 creduce-1]$ cat foo.i
typedef long long a;
struct __jmp_buf_tag   {
};
typedef struct __jmp_buf_tag sigjmp_buf[1];
sigjmp_buf jmp_buf;
int __sigsetjmp (sigjmp_buf, int);
typedef struct {
  a target;
} b;
extern a *target_p;
b *c;
extern void e (a);
void
d(void)
{
  if (__sigsetjmp(jmp_buf, 1)) {
    a target = *target_p;
    c->target = target;
    e(target);
  }
}
[hjl@gnu-skx-1 creduce-1]$ /usr/gcc-10.1.1-x32/bin/gcc -m32 -O2 -W foo.i -S
foo.i: In function ??d??:
foo.i:17:7: warning: variable ??target?? might be clobbered by ??longjmp?? or
??vfork?? [-Wclobbered]
   17 |     a target = *target_p;
      |       ^~~~~~
[hjl@gnu-skx-1 creduce-1]$ 

GCC 9.3 is OK.

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
                 CC|                            |rguenther at suse dot de
   Last reconfirmed|                            |2020-05-09
   Target Milestone|---                         |10.2
     Ever confirmed|0                           |1

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
Need -msse2 to trigger the bug.  This caused by r10-2807:

commit 48a31a09839b12127ce7c40d7adc4bd5bf1d3407
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Aug 26 10:35:59 2019 +0000

    re PR target/91522 (STV is slow)

    2019-08-26  Richard Biener  <rguenther@suse.de>

            PR target/91522
            PR target/91527
            * config/i386/i386-features.h (general_scalar_chain::defs_map):
            New member.
            (general_scalar_chain::replace_with_subreg): Remove.
            (general_scalar_chain::replace_with_subreg_in_insn): Likewise.
            (general_scalar_chain::convert_reg): Adjust signature.
            * config/i386/i386-features.c (scalar_chain::add_insn): Do not
            iterate over all defs of a reg.
            (general_scalar_chain::replace_with_subreg): Remove.
            (general_scalar_chain::replace_with_subreg_in_insn): Likewise.
            (general_scalar_chain::make_vector_copies): Populate defs_map,
            place copy only after defs that are used as vectors in the chain.
            (general_scalar_chain::convert_reg): Emit a copy for a specific
            def in a specific instruction.
            (general_scalar_chain::convert_op): All reg uses are converted
here.
            (general_scalar_chain::convert_insn): Emit copies for scalar
            uses of defs here.  Replace uses with the copies we created.
            Replace and convert the def.  Adjust REG_DEAD notes, remove
            REG_EQUIV/EQUAL notes.
            (general_scalar_chain::convert_registers): Only handle copies
            into the chain here.

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
271r.ce2 dump has

;; bb 0 artificial_defs: { d2(0){ }d5(1){ }d8(2){ }d9(6){ }d17(7){ }d34(16){
}d44(19){ }d47(20){ }d50(21){ }d53(22){ }d66(28){ }d69(29){ }d72(30){ }}
;; bb 0 artificial_uses: { }
;; lr  in        85
;; lr  use
;; lr  def       0 [ax] 1 [dx] 2 [cx] 6 [bp] 7 [sp] 16 [argp] 19 [frame] 20
[xmm0] 21 [xmm1] 22 [xmm2] 28 [mm0] 29 [mm1] 30 [mm2]
;; live  in     
;; live  gen     0 [ax] 1 [dx] 2 [cx] 6 [bp] 7 [sp] 16 [argp] 19 [frame] 20
[xmm0] 21 [xmm1] 22 [xmm2] 28 [mm0] 29 [mm1] 30 [mm2]
;; live  kill
;; lr  out       6 [bp] 7 [sp] 16 [argp] 19 [frame] 85
;; live  out     6 [bp] 7 [sp] 16 [argp] 19 [frame]
...
;; bb 2 artificial_defs: { }
;; bb 2 artificial_uses: { u0(6){ }u1(7){ }u2(16){ }u3(19){ }}
;; lr  in        6 [bp] 7 [sp] 16 [argp] 19 [frame] 85
;; lr  use       6 [bp] 7 [sp] 16 [argp] 19 [frame]
;; lr  def       0 [ax] 1 [dx] 2 [cx] 7 [sp] 8 [st] 9 [st(1)] 10 [st(2)] 11
[st(3)] 12 [st(4)] 13 [st(5)] 14 [st(6)] 15 [st(7)] 17 [flags] 18 [fpsr] 20
[xmm0] 21 [xmm1] 22 [xmm2] 23 [xmm3] 24 [xmm4] 25 [xmm5] 26 [xmm6] 27 [xmm7] 28
[mm0] 29 [mm1] 30 [mm2] 31 [mm3] 32 [mm4] 33 [mm5] 34 [mm6] 35 [mm7] 36 [r8] 37
[r9] 38 [r10] 39 [r11] 40 [r12] 41 [r13] 42 [r14] 43 [r15] 44 [xmm8] 45 [xmm9]
46 [xmm10] 47 [xmm11] 48 [xmm12] 49 [xmm13] 50 [xmm14] 51 [xmm15] 52 [xmm16] 53
[xmm17] 54 [xmm18] 55 [xmm19] 56 [xmm20] 57 [xmm21] 58 [xmm22] 59 [xmm23] 60
[xmm24] 61 [xmm25] 62 [xmm26] 63 [xmm27] 64 [xmm28] 65 [xmm29] 66 [xmm30] 67
[xmm31] 68 [k0] 69 [k1] 70 [k2] 71 [k3] 72 [k4] 73 [k5] 74 [k6] 75 [k7] 88
;; live  in      6 [bp] 7 [sp] 16 [argp] 19 [frame]
;; live  gen     0 [ax] 7 [sp] 17 [flags] 88
;; live  kill    17 [flags]
;; lr  out       6 [bp] 7 [sp] 16 [argp] 19 [frame] 85
;; live  out     6 [bp] 7 [sp] 16 [argp] 19 [frame]

Since IRA has

 /* DF_LIVE can't be used in the register allocator, too many other
     parts of the compiler depend on using the "classic" liveness
     interpretation of the DF_LR problem.  See PR38711.
     Remove the problem, so that we don't spend time updating it in
     any of the df_analyze() calls during IRA/LRA.  */
  if (optimize > 1) 
    df_remove_problem (df_live);
  gcc_checking_assert (df_live == NULL);

setjmp_vars_warning uses DF_LR info and gets the wrong result.

Why is DF_LR info so way off? Reg 85 isn't live at function entry
nor at BB 2 exit.

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
                 CC|rguenther at suse dot de           |law at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
             Target|                            |x86_64-*-*

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
IIRC Jeff was working on replacing -Wclobbered

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> ---
The problem is since df_lr_bb_local_compute has

       /* If the def is to only part of the reg, it does
           not kill the other defs that reach here.  */
        if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
          {
            unsigned int dregno = DF_REF_REGNO (def);
            bitmap_set_bit (&bb_info->def, dregno);
            bitmap_clear_bit (&bb_info->use, dregno);
          }

it doesn't consider

(insn 40 39 25 3 (set (subreg:SI (reg/v:DI 85 [ target ]) 4)
        (subreg:SI (reg:V2DI 90) 0)) "x.i":17:7 -1
     (nil))

as a def.

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> ---
STV generates:

        8d b6 00 00 00 00       lea    0x0(%esi),%esi
        a1 00 00 00 00          mov    0x0,%eax R_386_32        target_p
        83 ec 08                sub    $0x8,%esp
        f3 0f 7e 00             movq   (%eax),%xmm0
        a1 00 00 00 00          mov    0x0,%eax R_386_32        c
        66 0f 6f c8             movdqa %xmm0,%xmm1
        66 0f 7e 44 24 10       movd   %xmm0,0x10(%esp)
        66 0f 73 d1 20          psrlq  $0x20,%xmm1
        66 0f d6 00             movq   %xmm0,(%eax)
        66 0f 7e 4c 24 14       movd   %xmm1,0x14(%esp)
        ff 74 24 14             pushl  0x14(%esp)
        ff 74 24 14             pushl  0x14(%esp)
        e8 fc ff ff ff          call   <d+0x53> R_386_PC32      e

instead of

        8d b6 00 00 00 00       lea    0x0(%esi),%esi
        a1 00 00 00 00          mov    0x0,%eax R_386_32        target_p
        8b 0d 00 00 00 00       mov    0x0,%ecx R_386_32        c
        83 ec 08                sub    $0x8,%esp
        8b 50 04                mov    0x4(%eax),%edx
        8b 00                   mov    (%eax),%eax
        89 51 04                mov    %edx,0x4(%ecx)
        89 01                   mov    %eax,(%ecx)
        52                      push   %edx
        50                      push   %eax
        e8 fc ff ff ff          call   <d+0x3b> R_386_PC32      e

It is hard to tell if vector is faster.

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #6 from rguenther at suse dot de <rguenther at suse dot de> ---
On Tue, 12 May 2020, hjl.tools at gmail dot com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021
> 
> --- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> ---
> The problem is since df_lr_bb_local_compute has
> 
>        /* If the def is to only part of the reg, it does
>            not kill the other defs that reach here.  */
>         if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
>           {
>             unsigned int dregno = DF_REF_REGNO (def);
>             bitmap_set_bit (&bb_info->def, dregno);
>             bitmap_clear_bit (&bb_info->use, dregno);
>           }
> 
> it doesn't consider
> 
> (insn 40 39 25 3 (set (subreg:SI (reg/v:DI 85 [ target ]) 4)
>         (subreg:SI (reg:V2DI 90) 0)) "x.i":17:7 -1
>      (nil))
> 
> as a def.

Which it isn't since it sets the upper half of reg:DI 85 only.

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ubizjak at gmail dot com
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2020-May/545
                   |                            |630.html
           Keywords|                            |patch

--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> ---
A patch is posted at

https://gcc.gnu.org/pipermail/gcc-patches/2020-May/545630.html

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #8 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to rguenther@suse.de from comment #6)
> On Tue, 12 May 2020, hjl.tools at gmail dot com wrote:
> 
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021
> > 
> > --- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> ---
> > The problem is since df_lr_bb_local_compute has
> > 
> >        /* If the def is to only part of the reg, it does
> >            not kill the other defs that reach here.  */
> >         if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
> >           {
> >             unsigned int dregno = DF_REF_REGNO (def);
> >             bitmap_set_bit (&bb_info->def, dregno);
> >             bitmap_clear_bit (&bb_info->use, dregno);
> >           }
> > 
> > it doesn't consider
> > 
> > (insn 40 39 25 3 (set (subreg:SI (reg/v:DI 85 [ target ]) 4)
> >         (subreg:SI (reg:V2DI 90) 0)) "x.i":17:7 -1
> >      (nil))
> > 
> > as a def.
> 
> Which it isn't since it sets the upper half of reg:DI 85 only.

True.  But it is clearly incorrect that reg:DI 85 is live at function
entrance.

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by H.J. Lu <hjl@gcc.gnu.org>:

https://gcc.gnu.org/g:266f44a91c0c9705d3d18e82d7c5bab32927a18f

commit r11-446-g266f44a91c0c9705d3d18e82d7c5bab32927a18f
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Sun May 17 10:10:34 2020 -0700

    x86: Allow V1TI vector register pushes

    Add V1TI vector register push and split it after reload to a sequence
    of:

    (set (reg:P SP_REG) (plus:P SP_REG) (const_int -8)))
    (set (match_dup 0) (match_dup 1))

    so that STV pass can convert TI mode integer push to V1TI vector register
    push.  Rename has_non_address_hard_reg to pseudo_reg_set, combine calls
    of single_set and has_non_address_hard_reg to pseudo_reg_set, to ignore
    pseudo register push.

    Remove c-c++-common/dfp/func-vararg-mixed-2.c since it is compiled with
    -mpreferred-stack-boundary=2 and leads to segfault:

    Dump of assembler code for function __bid_nesd2:
       0x08049210 <+0>:     endbr32
       0x08049214 <+4>:     push   %esi
       0x08049215 <+5>:     push   %ebx
       0x08049216 <+6>:     call   0x8049130 <__x86.get_pc_thunk.bx>
       0x0804921b <+11>:    add    $0x8de5,%ebx
       0x08049221 <+17>:    sub    $0x20,%esp
       0x08049224 <+20>:    mov    0x30(%esp),%esi
       0x08049228 <+24>:    pushl  0x2c(%esp)
       0x0804922c <+28>:    call   0x804e600 <__bid32_to_bid64>
       0x08049231 <+33>:    mov    %esi,(%esp)
       0x08049234 <+36>:    movd   %edx,%xmm1
       0x08049238 <+40>:    movd   %eax,%xmm0
       0x0804923c <+44>:    punpckldq %xmm1,%xmm0
    => 0x08049240 <+48>:    movaps %xmm0,0x10(%esp)
       0x08049245 <+53>:    call   0x804e600 <__bid32_to_bid64>
       0x0804924a <+58>:    push   %edx
       0x0804924b <+59>:    push   %eax
       0x0804924c <+60>:    pushl  0x1c(%esp)
       0x08049250 <+64>:    pushl  0x1c(%esp)
       0x08049254 <+68>:    call   0x804b260 <__bid64_quiet_not_equal>
       0x08049259 <+73>:    add    $0x34,%esp
       0x0804925c <+76>:    pop    %ebx
       0x0804925d <+77>:    pop    %esi
       0x0804925e <+78>:    ret

    when libgcc is compiled with -msse2.  According to GCC manual:

    '-mpreferred-stack-boundary=NUM'
         Attempt to keep the stack boundary aligned to a 2 raised to NUM
         byte boundary.  If '-mpreferred-stack-boundary' is not specified,
         the default is 4 (16 bytes or 128-bits).

         *Warning:* If you use this switch, then you must build all modules
         with the same value, including any libraries.  This includes the
         system libraries and startup modules.

    c-c++-common/dfp/func-vararg-mixed-2.c, which was added by

    commit 3b2488ca6ece182f2136a20ee5fa0bb92f935b0f
    Author: H.J. Lu <hongjiu.lu@intel.com>
    Date:   Wed Jul 30 19:24:02 2008 +0000

        func-vararg-alternate-d128-2.c: New.

        2008-07-30  H.J. Lu  <hongjiu.lu@intel.com>
                    Joey Ye  <joey.ye@intel.com>

                * gcc.dg/dfp/func-vararg-alternate-d128-2.c: New.
                * gcc.dg/dfp/func-vararg-mixed-2.c: Likewise.

    isn't expected to work with libgcc.

    gcc/

            PR target/95021
            * config/i386/i386-features.c (has_non_address_hard_reg):
            Renamed to ...
            (pseudo_reg_set): This.  Return the SET expression.  Ignore
            pseudo register push.
            (general_scalar_to_vector_candidate_p): Combine single_set and
            has_non_address_hard_reg calls to pseudo_reg_set.
            (timode_scalar_to_vector_candidate_p): Likewise.
            * config/i386/i386.md (*pushv1ti2): New pattern.

    gcc/testsuite/

            PR target/95021
            * c-c++-common/dfp/func-vararg-mixed-2.c: Removed.
            * gcc.target/i386/pr95021-1.c: New test.
            * gcc.target/i386/pr95021-2.c: Likewise.
            * gcc.target/i386/pr95021-3.c: Likewise.
            * gcc.target/i386/pr95021-4.c: Likewise.
            * gcc.target/i386/pr95021-5.c: Likewise.

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #10 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed for GCC 11.

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

Rainer Orth <ro at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ro at gcc dot gnu.org

--- Comment #11 from Rainer Orth <ro at gcc dot gnu.org> ---
Two of the new tests FAIL on 32-bit Solaris/x86:

+FAIL: gcc.target/i386/pr95021-1.c scan-assembler movq[ \\t]%xmm[0-9]+,
\\\\(%esp\\\\)
+FAIL: gcc.target/i386/pr95021-3.c scan-assembler movq[ \\t]+[^\\n]*, %xmm

[Bug middle-end/95021] [10/11 Regression] Bogus -Wclobbered warning

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.2                        |10.3

--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10.2 is released, adjusting target milestone.

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
      Known to work|                            |11.0
            Summary|[10/11 Regression] Bogus    |[10 Regression] Bogus
                   |-Wclobbered warning         |-Wclobbered warning

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[ro at CeBiTec dot Uni-Bielefeld.DE]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #13 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
The failures reported in Comment 11 still exist on master, though.
Maybe it's too early to remove 11 from the regression list?

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to ro@CeBiTec.Uni-Bielefeld.DE from comment #13)
> The failures reported in Comment 11 still exist on master, though.
> Maybe it's too early to remove 11 from the regression list?

But that seems to be a new issue with the added testcases.  Can you open a
separate PR for this?

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[ro at CeBiTec dot Uni-Bielefeld.DE]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #15 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
> --- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> ---
> (In reply to ro@CeBiTec.Uni-Bielefeld.DE from comment #13)
>> The failures reported in Comment 11 still exist on master, though.
>> Maybe it's too early to remove 11 from the regression list?
>
> But that seems to be a new issue with the added testcases.  Can you open a
> separate PR for this?

Done now as PR testsuite/98676.  I was just a bit worried that the patch
would be backported to the gcc-10 branch as is, together with the (so
far ignored) failures.

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |98676

--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to ro@CeBiTec.Uni-Bielefeld.DE from comment #15)
> > --- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> ---
> > (In reply to ro@CeBiTec.Uni-Bielefeld.DE from comment #13)
> >> The failures reported in Comment 11 still exist on master, though.
> >> Maybe it's too early to remove 11 from the regression list?
> >
> > But that seems to be a new issue with the added testcases.  Can you open a
> > separate PR for this?
> 
> Done now as PR testsuite/98676.  I was just a bit worried that the patch
> would be backported to the gcc-10 branch as is, together with the (so
> far ignored) failures.

Sure.  We have dependencies to track this.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98676
[Bug 98676] gcc.target/i386/pr95021-1.c etc. FAIL

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

--- Comment #17 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by H.J. Lu <hjl@gcc.gnu.org>:

https://gcc.gnu.org/g:a512079ef40e442c1269ea1cc55f18790ba68449

commit r11-6669-ga512079ef40e442c1269ea1cc55f18790ba68449
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Jan 14 06:56:17 2021 -0800

    i386: Update PR target/95021 tests

    Also pass -mpreferred-stack-boundary=4 -mno-stackrealign to avoid
    disabling STV by:

      /* Disable STV if -mpreferred-stack-boundary={2,3} or
         -mincoming-stack-boundary={2,3} or -mstackrealign - the needed
         stack realignment will be extra cost the pass doesn't take into
         account and the pass can't realign the stack.  */
      if (ix86_preferred_stack_boundary < 128
          || ix86_incoming_stack_boundary < 128
          || opts->x_ix86_force_align_arg_pointer)
        opts->x_target_flags &= ~MASK_STV;

            PR target/98676
            * gcc.target/i386/pr95021-1.c: Add -mpreferred-stack-boundary=4
            -mno-stackrealign.
            * gcc.target/i386/pr95021-3.c: Likewise.

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021
Bug 95021 depends on bug 98676, which changed state.

Bug 98676 Summary: [11 Regression] gcc.target/i386/pr95021-1.c etc. FAIL
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98676

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.3                        |10.4

--- Comment #18 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10.3 is being released, retargeting bugs to GCC 10.4.

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.4                        |10.5

--- Comment #19 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 10.4 is being released, retargeting bugs to GCC 10.5.

[Bug middle-end/95021] [10 Regression] Bogus -Wclobbered warning

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95021

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
      Known to fail|                            |10.5.0
             Status|NEW                         |RESOLVED
   Target Milestone|10.5                        |11.0

--- Comment #20 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed in GCC 11.