[Bug tree-optimization/111432] New: `bool & (a|1)` is not optimized to just `bool`

[Bug tree-optimization/111432] New: `bool & (a|1)` is not optimized to just `bool`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111432

            Bug ID: 111432
           Summary: `bool & (a|1)` is not optimized to just `bool`
           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: ---

take:
```
int
foo3(int c, int bb)
{
  if ((bb & ~3)!=0) __builtin_unreachable();
  return (bb & (c|3));
}
int
foo_bool(int c, _Bool bb)
{
  return (bb & (c|7));
}
```
foo3 should be optimized to just `return bb`, likewise for foo_bool.

Note LLVM does this.

[Bug tree-optimization/111432] `bool & (a|1)` is not optimized to just `bool`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111432

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot gnu.org
   Last reconfirmed|                            |2023-10-10
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |ASSIGNED

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The reason why this is correct is:

a & (x | CST) -> (a & x) | (a & CST) -> // due to `a & CST -> a`
(a & x) | a -> a

So:
```
/* `a & (x | CST)` -> a if we know that (a & ~CST) == 0   */
(simplify
 (bit_and:c SSA_NAME@0 (bit_ior @1 INTEGER_CST@2))
 (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
      && wi::bit_and_not (get_nonzero_bits (@0), wi::to_wide (@2)) == 0)
  @0))
```

// a | (x & CST) simplifies down to `(a | x) & CST` but I don't see if that is
an improvement here as we still have 2 operations.

[Bug tree-optimization/111432] `bool & (a|1)` is not optimized to just `bool`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111432

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2023-October
                   |                            |/632988.html
           Keywords|                            |patch

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Patch posted:
https://gcc.gnu.org/pipermail/gcc-patches/2023-October/632988.html

[Bug tree-optimization/111432] `bool & (a|1)` is not optimized to just `bool`

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111432

--- 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:b18d1cabe2f9cccc0cad697e1e0bfd2abebb85f9

commit r14-4686-gb18d1cabe2f9cccc0cad697e1e0bfd2abebb85f9
Author: Andrew Pinski <pinskia@gmail.com>
Date:   Fri Oct 13 13:27:18 2023 -0700

    MATCH: [PR111432] Simplify `a & (x | CST)` to a when we know that (a &
~CST) == 0

    This adds the simplification `a & (x | CST)` to a when we know that
    `(a & ~CST) == 0`. In a similar fashion as `a & CST` is handle.

    I looked into handling `a | (x & CST)` but that I don't see any decent
    simplifications happening.

    OK? Bootstrapped and tested on x86_linux-gnu with no regressions.

            PR tree-optimization/111432

    gcc/ChangeLog:

            * match.pd (`a & (x | CST)`): New pattern.

    gcc/testsuite/ChangeLog:

            * gcc.dg/tree-ssa/bitops-7.c: New test.

[Bug tree-optimization/111432] `bool & (a|1)` is not optimized to just `bool`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111432

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

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

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