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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/104018] Comparison against 0 propagates into
 other statement causing no-CSE from happening
Date: Fri, 14 Jan 2022 08:08:44 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104018

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-01-14
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
The "unfortunate" thing is that FRE1 figures out they are equal but there's
no SSA name available with the value to replace the PHI node with ... it ne=
eds
PRE hoisting to apply the CSE which is too late.

It's DOM doing the equivalence propagation btw. (I think DOM is even the on=
ly
pass doing this).=