[Bug tree-optimization/102902] New: wrong code at -O3 on x86_64-linux-gnu (generated code hangs)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102902

            Bug ID: 102902
           Summary: wrong code at -O3 on x86_64-linux-gnu (generated code
                    hangs)
           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.

[575] % 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 20211022 (experimental) [master r12-4624-gae5c540662e] (GCC) 
[576] % 
[576] % gcctk -O2 small.c; ./a.out
[577] % 
[577] % gcctk -O3 small.c
[578] % timeout -s 9 10 ./a.out
Killed
[579] % 
[579] % cat small.c
int printf (const char *, ...);
int a, b, c, d, e, f;
int main() {
  int g;
  short h = 1;
  for (; e < 2; e++) {
  L1:
    f = 1;
    while (b > 0 || a > 0) {
      g++;
      h++;
      printf("%d", g);
    }
  L2:
    if (!h && (!c || a))
      goto L1;
    if (c)
      goto L2;
  }
  return 0;
}