[Bug tree-optimization/111679] New: `(~a) | (a ^ b)` is not simplified to `~(a & b)`

[Bug tree-optimization/111679] New: `(~a) | (a ^ b)` is not simplified to `~(a & b)`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111679

            Bug ID: 111679
           Summary: `(~a) | (a ^ b)` is not simplified to `~(a & b)`
           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: ---

Take:
```
int f(int a, int b)
{
        return a | ((~a) ^ b);
}

int f1(int a, int b)
{
        return (~a) | (a ^ b); // ~(a & b) or (~a) | (~b)
}
```

The only difference between these 2 functions is a is bitwise inversed. f is
able to be detected and simplified but not f1.

I Noticed this while working on PR 111282.

[Bug tree-optimization/111679] `(~a) | (a ^ b)` is not simplified to `~(a & b)`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111679

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-10-03
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |ASSIGNED

[Bug tree-optimization/111679] `(~a) | (a ^ b)` is not simplified to `~(a & b)`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111679

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
```
/* (~a) | (a ^ b)  -->  (~a) | (~b)
   (which might be done into ~(a & b) depending on if ~a is not a cmp)  */
(simplify
 (bit_ior:c @0 (bit_xor:c @1 @2))
 (with { bool wascmp; }
 (if (bitwise_inverted_equal_p (@0, @1, wascmp)
      && (!wascmp || element_precision (type) == 1))
  (bit_ior @0 (bit_not @2)))))
```

Still need some testcases.

[Bug tree-optimization/111679] `(~a) | (a ^ b)` is not simplified to `~(a & b)`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111679

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2023-October
                   |                            |/632386.html

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Patch posted:
https://gcc.gnu.org/pipermail/gcc-patches/2023-October/632386.html

[Bug tree-optimization/111679] `(~a) | (a ^ b)` is not simplified to `~(a & b)`

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111679

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Andrew Pinski <pinskia@gcc.gnu.org>:

https://gcc.gnu.org/g:975da6fa9170c9cf1ec4a9a9d8177f8561d464d1

commit r14-4543-g975da6fa9170c9cf1ec4a9a9d8177f8561d464d1
Author: Andrew Pinski <pinskia@gmail.com>
Date:   Mon Oct 9 11:07:08 2023 -0700

    MATCH: [PR111679] Add alternative simplification of `a | ((~a) ^ b)`

    So currently we have a simplification for `a | ~(a ^ b)` but
    that does not match the case where we had originally `(~a) | (a ^ b)`
    so we need to add a new pattern that matches that and uses
bitwise_inverted_equal_p
    that also catches comparisons too.

    OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

            PR tree-optimization/111679

    gcc/ChangeLog:

            * match.pd (`a | ((~a) ^ b)`): New pattern.

    gcc/testsuite/ChangeLog:

            * gcc.dg/tree-ssa/bitops-5.c: New test.

[Bug tree-optimization/111679] `(~a) | (a ^ b)` is not simplified to `~(a & b)`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111679

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed.