[Bug tree-optimization/107887] New: (bool0 > bool1) | bool1 is not optimized to bool0 | bool1

[Bug tree-optimization/107887] New: (bool0 > bool1) | bool1 is not optimized to bool0 | bool1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107887

            Bug ID: 107887
           Summary: (bool0 > bool1) | bool1 is not optimized to bool0 |
                    bool1
           Product: gcc
           Version: 13.0
            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
  Target Milestone: ---

Take:
```
_Bool max(_Bool aa, _Bool bb)
{
  bool t = aa > bb;
  return t | bb;
}
```
This should be optimized to just `return aa | bb;`
I accidently found this while working on PR 101805 .

The original testcase which I found it:
```
int ii(_Bool aa, _Bool bb)
{
  int c;
  int a = aa;
  int b = bb;
  if (a > b)
    c = a;
  else
    c = b;
  if (c)
    return 100;
  return c;
}
```

[Bug tree-optimization/107887] (bool0 > bool1) | bool1 is not optimized to bool0 | bool1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107887

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement

[Bug tree-optimization/107887] (bool0 > bool1) | bool1 is not optimized to bool0 | bool1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107887

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-11-28
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot gnu.org
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=107881

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
There is some discussion about this in bug 107881 comment #6 on how to
implement this inside reassociation .

I am going to try to figure out how to handle this there.

[Bug tree-optimization/107887] (bool0 > bool1) | bool1 is not optimized to bool0 | bool1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107887

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |NEW
           Assignee|pinskia at gcc dot gnu.org         |unassigned at gcc dot gnu.org

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Hmm, the code of reassociation is somewhat hard to follow. So I am not going to
work on this.

[Bug tree-optimization/107887] (bool0 > bool1) | bool1 is not optimized to bool0 | bool1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107887
Bug 107887 depends on bug 107881, which changed state.

Bug 107881 Summary: (a <= b) == (b >= a) should be optimized to (a == b)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107881

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |DUPLICATE

[Bug tree-optimization/107887] (bool0 > bool1) | bool1 is not optimized to bool0 | bool1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107887
Bug 107887 depends on bug 107881, which changed state.

Bug 107881 Summary: (a <= b) == (b >= a) should be optimized to (a == b)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107881

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |ASSIGNED
         Resolution|DUPLICATE                   |---

[Bug tree-optimization/107887] (bool0 > bool1) | bool1 is not optimized to bool0 | bool1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107887
Bug 107887 depends on bug 107881, which changed state.

Bug 107881 Summary: (a <= b) == (b >= a) should be optimized to (a == b)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107881

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

[Bug tree-optimization/107887] (bool0 > bool1) | bool1 is not optimized to bool0 | bool1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107887

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The bigger question on this is canonical form here, is it `a < b` or `~a & b`.
If it is `a < b` then we need the ability to match `a < b` as `~a < b` but that
might get complex with bitwise_inverted_equal_p ...