[Bug tree-optimization/117779] New: abs is not removed from a loop

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117779

            Bug ID: 117779
           Summary: abs is not removed from a loop
           Product: gcc
           Version: 15.0
            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:
```
int f(int r, int n){
  for(int i=0;i<n;i++)
    r = __builtin_abs(r);
  return r;
}
```


This really should be optimized to just `n > 0 ? abs(r) : r`.

`& 1` works though.