[Bug tree-optimization/126296] New: `(i <=> j > 0) | (i <=> j < 0)` should optimize to `i <> j` even with trapping

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126296

            Bug ID: 126296
           Summary: `(i <=> j > 0) | (i <=> j < 0)` should optimize to `i
                    <> j` even with trapping
           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
        Depends on: 126138
  Target Milestone: ---

Take:
```
#include <compare>
bool f(double i, double j)
{
  auto t = i<=>j;
  return (t < 0) | (t > 0);
}
```

This should/can be optimize to use LTGT_EXPR even with trapping.

I have a patch set already.
This gets optimized in phiopt4 with the patch set.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126138
[Bug 126138] `fp0 == fp1 || fp0 CMP fp1` can be combined always even with
trapping