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From: "law at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/114277] [11/12/13/14 Regression] Missed
 optimization: x*(x||b) => x
Date: Sat, 09 Mar 2024 03:56:52 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114277

Jeffrey A. Law <law at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at gcc dot gnu.org,
                   |                            |rzinsly at ventanamicro do=
t com

--- Comment #2 from Jeffrey A. Law <law at gcc dot gnu.org> ---
The other approach we could take (and which I think may have certain
advantages) would be to first realize this is a multiplication by a boolean
(0/1) value.  That's just a conditional move.  If we then rewrote as a
conditional move there's a reasonable chance we'd be able to further simpli=
fy.

The biggest problem with this approach is if we're aggressively transforming
into  conditional moves in gimple, the expanders will need improvement,
particularly on targets that don't have conditional moves.

Raphael has a TODO in this space.   He may have further thoughts.=