[Bug tree-optimization/110984] New: phiopt's spaceship_replacement should support cast and !=

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110984

            Bug ID: 110984
           Summary: phiopt's spaceship_replacement should support cast and
                    !=
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: pinskia at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Testcase:
```
int f5n (double i, double j)
{
        signed char c;
        if (i != j)
        {
          if (i < j)
           c = 1;
         else
           c = -1;
        }
        else
           c = 0;
        unsigned int t1 = c;
        return t1 != (unsigned int)-1;
}
```