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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/66502] SCCVN can't handle PHIs optimistically optimally
Date: Mon, 03 Jan 2022 09:50:35 +0000	[thread overview]
Message-ID: <bug-66502-4-Zbki77goAF@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-66502-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66502

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
      Known to work|                            |10.3.1
             Status|ASSIGNED                    |RESOLVED

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #5)
> (In reply to Richard Biener from comment #4)
> > SCCVN preference changed.  Missed optimization remains (now the other
> > variant).
> 
> GCC 10 looks like it can handle both now. I don't know if that means this
> can be marked as fixed though.

So it looks like we now first value-number j to a (backedge not executable)
and in the second iteration (backedge executable) we value-number it to i.
I guess the special-casing of a single executable edge makes this work now
and also ensure we don't oscillate between both choices.

  parent reply	other threads:[~2022-01-03  9:50 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-66502-4@http.gcc.gnu.org/bugzilla/>
2015-06-11  9:19 ` rguenth at gcc dot gnu.org
2015-08-13  7:06 ` rguenth at gcc dot gnu.org
2015-08-13  7:11 ` rguenth at gcc dot gnu.org
2021-12-13  8:31 ` pinskia at gcc dot gnu.org
2022-01-03  9:50 ` rguenth at gcc dot gnu.org [this message]
2022-01-03  9:50 ` cvs-commit at gcc dot gnu.org
2022-01-07  6:38 ` pinskia at gcc dot gnu.org

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