[Bug debug/107110] New: failure (length) with -fcompare-debug at -O1 and above

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107110

            Bug ID: 107110
           Summary: failure (length) with -fcompare-debug at -O1 and above
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

It appears to be a regression from 10.* and affect 11.* and later. 

Compiler Explorer: https://godbolt.org/z/Gvh15c5KE

[529] % 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 20221001 (experimental) [master r13-3010-g2555071c954] (GCC) 
[530] % 
[530] % gcctk -O1 -fcompare-debug small.c
gcctk: error: small.c: ‘-fcompare-debug’ failure (length)
[531] % 
[531] % cat small.c
int a, b;
void c() {
  int d, e = 1, f = 1, g, h = 0;
  for (; 1; h++) {
    if (d)
      f = 0;
    if (d)
      break;
    if (g)
      goto L;
    g = f;
  }
  for (; h < 1;)
  L:
    for (;;) {
      int j, k = e;
      if (a) {
        break;
        ;
      }
      e = 0;
      while (b <= k)
        ;
      break;
      &j;
    }
}
int main() {
  if (a)
    c();
  return 0;
}