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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/112104] loop of ^1 should just be reduced to
 ^(n&1)
Date: Fri, 27 Oct 2023 13:08:11 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D112104

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2023-10-27
             Status|UNCONFIRMED                 |NEW

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  I think it should apply even to

int
foo(long n3, int j, int x) {
  for(int i=3D0; i<n3; i++)
    j=3Dj^x;
  return j;
}

which alternates between 'j' and 'j^x', thus the result
is n3&1 ? j^x : j?

I wonder if there's some online symbolic calculus service that we can
feed IL during compilation ;)=