[Bug tree-optimization/126227] New: `(inta > int b) - (inta < intb)` should be recongized as a shipship operator

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126227

            Bug ID: 126227
           Summary: `(inta > int b) - (inta < intb)` should be recongized
                    as a shipship operator
           Product: gcc
           Version: 17.0
            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 cmp_int_asc(int a, int b) {
     return (a < b) ? -1 : (a > b ? 1 : 0);
}

int cmp_int_asc_2(int a, int b) {
    return (a < b) ? -1 : (a > b ? 1 : 0);
}

int cmp_int_asc_branchless(int a, int b) {
    return (a > b) - (a < b);
}
```
cmp_int_asc and cmp_int_asc_2 is reconigzed as a shipship operator but
cmp_int_asc_branchless is not.

Note `(a < b) - (a > b)` is a shapeship operator with lhs and rhs swapped.