[Bug tree-optimization/126937] New: wrong code at -O{s,2,3} on x86_64-linux-gnu

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126937

            Bug ID: 126937
           Summary: wrong code at -O{s,2,3} on x86_64-linux-gnu
           Product: gcc
           Version: 16.0
            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: ---

Compiler Explorer: https://godbolt.org/z/x4bv6qjGh

Note:
- fails: trunk
- works: 16.2 and earlier

[574] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/home/suz/suz-local/software/local/gcc-trunk/bin/../libexec/gcc/x86_64-pc-linux-gnu/17.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--enable-checking=yes --prefix=/local/suz-local/software/local/gcc-trunk
--enable-sanitizers --enable-languages=c,c++,lto --disable-werror
--disable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 17.0.0 20260819 (experimental) (GCC) 
[575] % 
[575] % gcctk -O1 small.c; ./a.out
[576] % 
[576] % gcctk -O2 small.c
[577] % ./a.out
Segmentation fault
[578] % 
[578] % cat small.c
int *a, b, d;
short c;
int main() {
  int f;
 L:
  b = ~(65535 << d);
  c = b ^ 1;
  if (c > b) {
    f = 0;
    if (c) {
      f = b;
      d = (b / c) && c;
      if (!b)
        goto L;
    }
    if (f >= 0)
      *a = 0;
  }
  return 0;
}