[Bug tree-optimization/108164] New: wrong code with "-O3 -fno-tree-dce" on x86_64-linux-gnu

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108164

            Bug ID: 108164
           Summary: wrong code with "-O3 -fno-tree-dce" 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: ---

It appears to be a regression from 11.*, and affects 12.* and the trunk.

Compiler Explorer: https://godbolt.org/z/Ko61s9WP4


[580] % 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/13.0.0/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++ --disable-werror --enable-multilib
--with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20221218 (experimental) [master r13-4763-g92bc3617572] (GCC) 
[581] % 
[581] % gcctk -O3 small.c; ./a.out
[582] % 
[582] % gcctk -O3 -fno-tree-dce small.c
[583] % ./a.out
Floating point exception
[584] % 
[584] % cat small.c
int a, b, c;
int main() {
  int e = -1;
  short f = -1;
  for (; c < 1; c++)
    while (f >= e)
      f++;
  for (; a < 2; a++) {
    short g = ~(~b | ~f);
    int h = -g;
    int i = (3 / ~h) / ~b;
    b = i;
  }
  return 0;
}