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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/55614] [4.6/4.7 Regression] vector extensions cause movdqa to be generated for memcpy on unaligned buffer
Date: Fri, 07 Dec 2012 15:29:00 -0000	[thread overview]
Message-ID: <bug-55614-4-LKeYAkYmUn@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-55614-4@http.gcc.gnu.org/bugzilla/>


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55614

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-12-07 15:28:30 UTC ---
(In reply to comment #5)
> How can a union have alignment 8 if it contains a field with alignment 128? 
> That should only happen if the field is a bit-field...

That is what the memcpy folding folds it to.  We could perhaps stop for 4.6/4.7
doing such replacements in memcpy folding if it would try to decrease alignment
of some aggregate, but then we risk regressing generated code quality.


  parent reply	other threads:[~2012-12-07 15:29 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-07 12:15 [Bug c/55614] New: " soren.sandmann at gmail dot com
2012-12-07 13:59 ` [Bug c/55614] " mikpe at it dot uu.se
2012-12-07 14:06 ` [Bug c/55614] [4.6/4.7 Regression] " jakub at gcc dot gnu.org
2012-12-07 14:30 ` [Bug tree-optimization/55614] " jakub at gcc dot gnu.org
2012-12-07 14:56 ` jamborm at gcc dot gnu.org
2012-12-07 14:57 ` ebotcazou at gcc dot gnu.org
2012-12-07 15:29 ` jakub at gcc dot gnu.org [this message]
2012-12-07 15:41 ` ebotcazou at gcc dot gnu.org
2012-12-09 21:00 ` siarhei.siamashka at gmail dot com
2012-12-09 22:25 ` siarhei.siamashka at gmail dot com
2013-04-03  9:47 ` rguenth at gcc dot gnu.org
2013-04-12 15:15 ` [Bug tree-optimization/55614] [4.7 " jakub at gcc dot gnu.org
2014-06-12 13:20 ` rguenth at gcc dot gnu.org

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