[Bug tree-optimization/102131] New: wrong code at -O1 and above on x86_64-linux-gnu

[zhendong.su at inf dot ethz.ch via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102131

            Bug ID: 102131
           Summary: wrong code at -O1 and above on x86_64-linux-gnu
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

This appears to be a recent regression.

[594] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/12.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--prefix=/local/suz-local/software/local/gcc-trunk --enable-languages=c,c++
--disable-werror --enable-multilib --with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20210830 (experimental) [master revision
02dbf5d1273:023508d4548:d73c44800b53c7e130da29e4eff1960b8311ffcd] (GCC) 
[595] % 
[595] % gcctk -O0 small.c; ./a.out
[596] % 
[596] % gcctk -O1 small.c
[597] % ./a.out
Aborted
[598] % 
[598] % cat small.c
int a;
int main() {
  unsigned b = 0;
  int c = 1;
  for (; b < 3; b++) {
    while (c < b)
      __builtin_abort ();
    for (a = 0; a < 3; a++)
      c++;
  }
  return 0;
}