[Bug tree-optimization/109702] New: [14 Regression] Wrong code with if and __builtin_bswap and others

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109702

            Bug ID: 109702
           Summary: [14 Regression] Wrong code with if and __builtin_bswap
                    and others
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: critical
          Priority: P3
         Component: tree-optimization
          Assignee: pinskia at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

I totally messed up the match.pd patterns such that we start to transform:
```
unsigned f(unsigned t, unsigned t1)
{
  if (t != 0)
    return __builtin_bswap32(t1);
  return 0;
}
```
To just `return __builtin_bswap32(t1)` . I only noticed this after the review
of the patch for CLRSB
(https://gcc.gnu.org/pipermail/gcc-patches/2023-May/617228.html ) but the
review didn't fully notice how it was incorrect; just noticed there was an
unused capture.