[Bug tree-optimization/109906] New: a rrotate (32-b) -> a lrotate b

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109906

            Bug ID: 109906
           Summary: a rrotate (32-b) -> a lrotate b
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
static inline
unsigned rotateright(unsigned x, int t)
{
  if (t >= 32) __builtin_unreachable();
  unsigned tl = x >> (t);
  unsigned th = x << (32-t);
  return tl | th;
}

unsigned rotateleft(unsigned t, int x)
{
  return rotate (t, 32-x);
}
```

I would have assumed GCC would produce a rotate left for rotateleft but does
not currently.