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From: "aldyh at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/104639] [12 Regression] Useless loop not fully optimized anymore
Date: Thu, 03 Mar 2022 14:04:07 +0000	[thread overview]
Message-ID: <bug-104639-4-RKi040JAFM@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-104639-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104639

--- Comment #9 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
(In reply to Andrew Macleod from comment #8)
> (In reply to Richard Biener from comment #3)

> Curious question, if that was an 'if' instead of a return using _3, the
> threader would probably thread the PHI away?  ie:
>   <bb 4> [local count: 118111600]:
>   # i_6 = PHI <i_2(D)(2), 6(3)>
>   _3 = i_6 != 0;
>   if (_3 != 0)
>     goto <bb7>
>   else
>     goto <bb8>
> 
> I don't suppose there is any possible future enhancement that would let us
> thread into returns like this?  Or maybe its not common enough?

Sure, the threader can't thread the current situation because it only does
conditionals not PHIs.  If that were an if, it should be able to thread it.

  parent reply	other threads:[~2022-03-03 14:04 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-22 12:53 [Bug tree-optimization/104639] New: " denis.campredon at gmail dot com
2022-02-22 13:07 ` [Bug tree-optimization/104639] [12 Regression] " jakub at gcc dot gnu.org
2022-02-22 13:16 ` jakub at gcc dot gnu.org
2022-02-22 15:23 ` rguenth at gcc dot gnu.org
2022-02-22 15:36 ` jakub at gcc dot gnu.org
2022-02-22 17:40 ` denis.campredon at gmail dot com
2022-02-22 18:06 ` jakub at gcc dot gnu.org
2022-03-03 11:36 ` aldyh at gcc dot gnu.org
2022-03-03 13:57 ` amacleod at redhat dot com
2022-03-03 14:04 ` aldyh at gcc dot gnu.org [this message]
2022-03-03 14:28 ` amacleod at redhat dot com
2022-03-03 15:04 ` aldyh at gcc dot gnu.org
2022-04-04 13:58 ` jakub at gcc dot gnu.org
2022-04-08 16:44 ` jakub at gcc dot gnu.org
2022-04-11  8:45 ` cvs-commit at gcc dot gnu.org
2022-04-11  9:03 ` jakub at gcc dot gnu.org

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