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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/110891] [14 Regression] Dead Code Elimination
 Regression since r14-2674-gd0de3bf9175
Date: Sat, 26 Aug 2023 06:35:44 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110891

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

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I have a patch for what I laid out in comment #3 and it solves the original
issue too because after ifcombine we have:
  _24 =3D _28 =3D=3D &c;
  _18 =3D _28 =3D=3D &d;
  _8 =3D _18 | _24;
  _25 =3D _28 =3D=3D &a;
  _20 =3D _8 | _25;
  if (_20 !=3D 0)
    goto <bb 4>; [99.98%]
  else
    goto <bb 3>; [0.02%]

  <bb 3> [local count: 210453]:
  __assert_fail ("", "", 4, &__PRETTY_FUNCTION__);

  <bb 4> [local count: 536765685]:
  _6 =3D _28 =3D=3D &c;
  _13 =3D _28 =3D=3D &d;
  _9 =3D _6 | _13;
  _27 =3D _28 =3D=3D &a;
  _17 =3D _9 | _27;
  if (_17 !=3D 0)
    goto <bb 6>; [99.98%]
  else
    goto <bb 5>; [0.02%]

Which then obviously gets optimized by DOM2.=