[Bug target/96402] New: [10/11 Regression] Wrong code with -moutline-atomics

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96402

            Bug ID: 96402
           Summary: [10/11 Regression] Wrong code with -moutline-atomics
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: rth at gcc dot gnu.org
  Target Milestone: ---
              Host: aarch64-linux-gnu

The following is miscompiled:

$ cat x.c
#include <stdio.h>

int main(void) {
  __int128 a = 0;
  __sync_val_compare_and_swap(&a, 0, 1);
  printf("a:%d\n", (int)a);
  if (a == 0)
    __builtin_abort ();
  return 0;
}

$ gcc x.c -moutline-atomics && ./a.out 
a:0
Aborted (core dumped)

$ gcc x.c -mno-outline-atomics && ./a.out 
a:1