[Bug tree-optimization/94882] New: Failure to optimize and+or+sub into xor+not

[Bug tree-optimization/94882] New: Failure to optimize and+or+sub into xor+not

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94882

            Bug ID: 94882
           Summary: Failure to optimize and+or+sub into xor+not
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gabravier at gmail dot com
  Target Milestone: ---

int f(int x, int y)
{
    return (x & y) - (x | y) - 1;
}

This can be optimized to `~(x ^ y)`. LLVM does this transformation, but GCC
does not.

[Bug tree-optimization/94882] Failure to optimize and+or+sub into xor+not

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94882

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-04-30
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

[Bug tree-optimization/94882] Failure to optimize and+or+sub into xor+not

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94882

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jeff Law <law@gcc.gnu.org>:

https://gcc.gnu.org/g:553c6572061f6f9ef92514e8f13de95d509ad614

commit r11-1771-g553c6572061f6f9ef92514e8f13de95d509ad614
Author: Jeff Law <law@redhat.com>
Date:   Wed Jul 1 14:44:07 2020 -0600

    match.pd: (x & y) - (x | y) - 1 -> ~(x ^ y) simplification [PR94882]

    gcc/
            PR tree-optimization/94882
            * match.pd (x & y) - (x | y) - 1 -> ~(x ^ y): New simplification.

    gcc/testsuite/
            PR tree-optimization/94882
            * gcc.dg/tree-ssa/pr94882.c: New test.
            * gcc.dg/tree-ssa/pr94882-1.c: New test.
            * gcc.dg/tree-ssa/pr94882-2.c: New test.
            * gcc.dg/tree-ssa/pr94882-3.c: New test.

[Bug tree-optimization/94882] Failure to optimize and+or+sub into xor+not

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94882

Jeffrey A. Law <law at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at redhat dot com
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #3 from Jeffrey A. Law <law at redhat dot com> ---
This should be fixed on the trunk now.