[Bug tree-optimization/110982] New: (unsigned)(signed_char) != (unsigned)-1 is never changed back into signed_char != -1

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110982

            Bug ID: 110982
           Summary: (unsigned)(signed_char) != (unsigned)-1 is never
                    changed back into signed_char != -1
           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: ---

While looking into a failure after improving VRP, I see we never translate
this:
```
bool f(signed char t)
{
  unsigned int t1 = t;
  return t1 != (unsigned int)-1;
}
```
into:
```
bool f0(signed char t)
{
  return t != -1;
}
```