[Bug tree-optimization/121001] New: frange on float_var*0.f includes NaN even if float_var does not include NaN

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121001

            Bug ID: 121001
           Summary: frange on float_var*0.f includes NaN even if float_var
                    does not include NaN
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
            Blocks: 85316
  Target Milestone: ---

Take:
```
float f(float a)
{
  if (a == a) {
    float t =  a*0.f;
    if (t != t) __builtin_trap ();
    return t;
  }
  return a;
}
```

The trap should be optimized away as a can only be 0.0 or -0.0 and not a NaN.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85316
[Bug 85316] [meta-bug] VRP range propagation missed cases