[Bug tree-optimization/104281] New: wrong code at -O3

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104281

            Bug ID: 104281
           Summary: wrong code at -O3
           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: ---

It is a recent regression and likely related to PR 104280 and PR 104279, but it
only reproduces at -O3. 

[537] % 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 20220129 (experimental) [master r12-6930-gf6f2d6cfec1] (GCC) 
[538] % 
[538] % gcctk -O2 small.c; ./a.out
[539] % 
[539] % gcctk -O3 small.c
[540] % timeout -s 9 5 ./a.out
Killed
[541] % 
[541] % cat small.c
unsigned a = 1;
int b, c = 2;
long d;
int main() {
  while (1) {
    int m = a;
  L:
    a = ~(-(m || b & d));
    b = ((1 ^ a) / c);
    if (b)
      goto L;
    break;
  }
  return 0;
}