[Bug regression/97981] New: [11 regression] 32-bit x86 'gcc.dg/atomic/c11-atomic-exec-1.c' execution test

[Bug regression/97981] New: [11 regression] 32-bit x86 'gcc.dg/atomic/c11-atomic-exec-1.c' execution test

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97981

            Bug ID: 97981
           Summary: [11 regression] 32-bit x86
                    'gcc.dg/atomic/c11-atomic-exec-1.c' execution test
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: regression
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tschwinge at gcc dot gnu.org
  Target Milestone: ---

Per my testing, for 32-bit x86 (x86_64-pc-linux-gnu '-m32'), something in
71e234a5c94ddaef4070b3a74cf6d867dfe1a24b..fbd4553d99bc918b645194da1dba9e8f5f1cdece
causes:

    @@ -209352,17 +209628,17 @@ PASS: gcc.dg/atomic/c11-atomic-exec-1.c   -O0 
execution test
    PASS: gcc.dg/atomic/c11-atomic-exec-1.c   -O1  (test for excess errors)
    PASS: gcc.dg/atomic/c11-atomic-exec-1.c   -O1  execution test
    PASS: gcc.dg/atomic/c11-atomic-exec-1.c   -O2  (test for excess errors)
    [-PASS:-]{+FAIL:+} gcc.dg/atomic/c11-atomic-exec-1.c   -O2  execution test
    PASS: gcc.dg/atomic/c11-atomic-exec-1.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none  (test for excess errors)
    [-PASS:-]{+FAIL:+} gcc.dg/atomic/c11-atomic-exec-1.c   -O2 -flto
-fno-use-linker-plugin -flto-partition=none  execution test
    PASS: gcc.dg/atomic/c11-atomic-exec-1.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects  (test for excess errors)
    [-PASS:-]{+FAIL:+} gcc.dg/atomic/c11-atomic-exec-1.c   -O2 -flto
-fuse-linker-plugin -fno-fat-lto-objects  execution test
    PASS: gcc.dg/atomic/c11-atomic-exec-1.c   -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions  (test for excess
errors)
    [-PASS:-]{+FAIL:+} gcc.dg/atomic/c11-atomic-exec-1.c   -O3
-fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions 
execution test
    PASS: gcc.dg/atomic/c11-atomic-exec-1.c   -O3 -g  (test for excess errors)
    [-PASS:-]{+FAIL:+} gcc.dg/atomic/c11-atomic-exec-1.c   -O3 -g  execution
test
    PASS: gcc.dg/atomic/c11-atomic-exec-1.c   -Os  (test for excess errors)
    [-PASS:-]{+FAIL:+} gcc.dg/atomic/c11-atomic-exec-1.c   -Os  execution test

No further details in the '*.log* file.

[Bug target/97981] [11 regression] 32-bit x86 'gcc.dg/atomic/c11-atomic-exec-1.c' execution test

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97981

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |needs-bisection, wrong-code
             Status|UNCONFIRMED                 |NEW
             Target|                            |i?86-*-*
   Target Milestone|---                         |11.0
   Last reconfirmed|                            |2020-11-25
          Component|regression                  |target
           Priority|P3                          |P1
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
IIRC I've also seen this.

[Bug target/97981] [11 regression] 32-bit x86 'gcc.dg/atomic/c11-atomic-exec-1.c' execution test

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97981

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |marxin at gcc dot gnu.org,
                   |                            |muecker at gwdg dot de
      Known to fail|                            |11.0
      Known to work|                            |10.2.0
           Keywords|needs-bisection             |
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=98029

--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Confirmed, started with r11-5188-g32934a4f45a72144.

There's reduced test-case:

$ cat atomic.i
int main(void) {
  static volatile _Atomic(double) a, b = (double)((0));
  if ((a = b) != ((double)((0))))
    __builtin_abort();

  return 0;
}

$ gcc -g atomic.i -m32 -c -O2 && gcc-10 -m32 -latomic atomic.o && valgrind
./a.out
==2400== Memcheck, a memory error detector
==2400== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==2400== Using Valgrind-3.16.1 and LibVEX; rerun with -h for copyright info
==2400== Command: ./a.out
==2400== 
==2400== Conditional jump or move depends on uninitialised value(s)
==2400==    at 0x8049081: main (atomic.i:3)
==2400== 
==2400== Conditional jump or move depends on uninitialised value(s)
==2400==    at 0x8049087: main (atomic.i:3)
==2400== 
==2400== 
==2400== Process terminating with default action of signal 6 (SIGABRT): dumping
core
==2400==    at 0x40C17D6: raise (in /lib/libc-2.32.so)
==2400==    by 0x40A9313: abort (in /lib/libc-2.32.so)
==2400==    by 0x8049054: main.cold (atomic.i:4)
==2400==    by 0x40AAF75: (below main) (in /lib/libc-2.32.so)
==2400== 
==2400== HEAP SUMMARY:
==2400==     in use at exit: 0 bytes in 0 blocks
==2400==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==2400== 
==2400== All heap blocks were freed -- no leaks are possible
==2400== 
==2400== Use --track-origins=yes to see where uninitialised values come from
==2400== For lists of detected and suppressed errors, rerun with: -s
==2400== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
Aborted (core dumped)

[Bug target/97981] [11 regression] 32-bit x86 'gcc.dg/atomic/c11-atomic-exec-1.c' execution test since r11-5188-g32934a4f45a72144

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97981

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
The revision causes the following diff in GENERIC:

@@ -10,8 +10,8 @@
     static atomic volatile double a;
     static atomic volatile double b = 0.0;
   # DEBUG BEGIN STMT;
-  if (TARGET_EXPR <D.1886, TARGET_EXPR <D.1885, (void) (D.1885 =
VIEW_CONVERT_EXPR<double>(__atomic_load_8 ((const volatile void *) &b, 5)))>>;
-  __atomic_store_8 ((volatile void *) &a, VIEW_CONVERT_EXPR<long long unsigned
int>(D.1886), 5);, D.1886 != 0.0;)
+  if (TARGET_EXPR <D.1885, (double) b>;
+  __atomic_store_8 ((volatile void *) &a, VIEW_CONVERT_EXPR<long long unsigned
int>(D.1885), 5);, D.1885 != 0.0;)
     {
       # DEBUG BEGIN STMT;
       __builtin_abort ();

[Bug target/97981] [11 regression] 32-bit x86 'gcc.dg/atomic/c11-atomic-exec-1.c' execution test since r11-5188-g32934a4f45a72144

[muecker at gwdg dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97981

--- Comment #4 from Martin Uecker <muecker at gwdg dot de> ---
I think the code to drop qualifiers needs to be moved below the check for
atomic. I will look into it. (I wonder why this passed checks for me).

[Bug target/97981] [11 regression] 32-bit x86 'gcc.dg/atomic/c11-atomic-exec-1.c' execution test since r11-5188-g32934a4f45a72144

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97981

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Martin Uecker <uecker@gcc.gnu.org>:

https://gcc.gnu.org/g:a19a242c708060e067b4fd5a76995144e6f239d0

commit r11-5832-ga19a242c708060e067b4fd5a76995144e6f239d0
Author: Martin Uecker <muecker@gwdg.de>
Date:   Mon Dec 7 23:51:25 2020 +0100

    C: Fix atomic loads. [PR97981]

    To handle atomic loads correctly, we need to move the code that
    drops qualifiers in lvalue conversion after the code that
    handles atomics.

    2020-12-07  Martin Uecker  <muecker@gwdg.de>

    gcc/c/
            PR c/97981
            * c-typeck.c (convert_lvalue_to_rvalue): Move the code
            that drops qualifiers to the end of the function.

    gcc/testsuite/
            PR c/97981
            * gcc.dg/pr97981.c: New test.
            * gcc.dg/pr60195.c: Adapt test.

[Bug target/97981] [11 regression] 32-bit x86 'gcc.dg/atomic/c11-atomic-exec-1.c' execution test since r11-5188-g32934a4f45a72144

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97981

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Assuming fixed.  Haven't seen the FAILs since Dec 8th.