[Bug tree-optimization/104519] New: wrong code at -Os on x86_64-linux-gnu

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104519

            Bug ID: 104519
           Summary: wrong code at -Os 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.

[682] % 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/12.0.1/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 12.0.1 20220213 (experimental) [master r12-7216-g7e204bd2f18] (GCC) 
[683] % 
[683] % gcctk -O1 small.c; ./a.out
[684] % 
[684] % gcctk -Os small.c
[685] % ./a.out
Aborted
[686] % 
[686] % cat small.c
char a, b;
int main() {
  for (b = -7; b; b += 3)
    if (a)
      __builtin_abort();
  return 0;
}