https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114793

            Bug ID: 114793
           Summary: wrong code at -O1 with "-fschedule-insns2
                    -fselective-scheduling2" on x86_64-linux-gnu (the
                    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: ---

It seems to be a recent regression as it does not reproduce with 13.2 and
earlier.

Compiler Explorer: https://godbolt.org/z/b3cc1MqP9

[538] % 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/14.0.1/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
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.1 20240421 (experimental) (GCC) 
[539] % 
[539] % gcctk -O0 small.c
[540] % ./a.out
[541] % 
[541] % gcctk -O1 -fschedule-insns2 -fselective-scheduling2 small.c
[542] % timeout -s 9 10 ./a.out
Killed
[543] % 
[543] % cat small.c
int printf(const char *, ...);
volatile int a;
int b, c, d = 1, e, f;
int main() {
  int g = 1;
  for (; b; b -= d)
    g = e;
  for (; c < 2; c++) {
    if (g) {
      if (!d)
        printf("%d", f);
      continue;
    }
    a;
  }
  return 0;
}

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