[Bug tree-optimization/110919] [14 Regression] Dead Code Elimination Regression at -O3 since r14-1691-gbc5a2c2e793

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110919

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 = _4 != 1;
Folded into: _23 = (_Bool) _3;


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

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