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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/110919] [14 Regression] Dead Code Elimination
 Regression at -O3 since r14-1691-gbc5a2c2e793
Date: Sun, 06 Aug 2023 17:12:03 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110919

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-08-06
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.


Note I think what EVRP produces for some thing makes it harder to optimize =
too.

EVRP does:

Folding statement: _23 =3D _4 !=3D 1;
Folded into: _23 =3D (_Bool) _3;


And at the end we get:
  _19 =3D _6 =3D=3D iftmp.1_8;
  _3 =3D iftmp.1_8 ^ 1;
  _21 =3D (_Bool) _3;
  _23 =3D _6 !=3D 0;
  _10 =3D _19 & _23;
  _5 =3D _10 & _21;

Which is basically:
(a =3D=3D b) & (a =3D=3D 0) & (b !=3D 0)=