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From: "law at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/65177] [5 Regression]: extend jump thread for finite state automata causes miscompilation
Date: Wed, 11 Mar 2015 21:45:00 -0000	[thread overview]
Message-ID: <bug-65177-4-oG6OyCjoiT@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-65177-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65177

--- Comment #15 from Jeffrey A. Law <law at redhat dot com> ---
Basically the way this works is we record the SSA_NAMEs that are being
duplicated during block copying.  For any duplicated SSA_NAME, if > 1 instance
of it is live at a join point in the CFG, then update_ssa will create a PHI and
merge the values.  

I can't offhand think of any reason why it wouldn't work here if the names were
properly marked.  But I haven't looked at the before/after CFGs to see if
there's something unique in this case.  In fact, I haven't looked at it at all
at this point.


  parent reply	other threads:[~2015-03-11 21:45 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-23 15:49 [Bug tree-optimization/65177] New: " marxin at gcc dot gnu.org
2015-02-23 15:58 ` [Bug tree-optimization/65177] " rguenth at gcc dot gnu.org
2015-02-23 16:19 ` trippels at gcc dot gnu.org
2015-02-23 17:41 ` marxin at gcc dot gnu.org
2015-02-23 17:48 ` spop at gcc dot gnu.org
2015-02-23 17:49 ` spop at gcc dot gnu.org
2015-02-25 21:33 ` mpolacek at gcc dot gnu.org
2015-02-25 23:05 ` spop at gcc dot gnu.org
2015-03-09 14:26 ` jakub at gcc dot gnu.org
2015-03-10 22:08 ` law at redhat dot com
2015-03-10 22:39 ` spop at gcc dot gnu.org
2015-03-10 22:42 ` spop at gcc dot gnu.org
2015-03-10 22:49 ` law at redhat dot com
2015-03-10 22:57 ` spop at gcc dot gnu.org
2015-03-10 23:03 ` law at redhat dot com
2015-03-11 16:27 ` spop at gcc dot gnu.org
2015-03-11 21:45 ` law at redhat dot com [this message]
2015-03-13 20:47 ` spop at gcc dot gnu.org
2015-03-13 21:05 ` spop at gcc dot gnu.org
2015-03-16 21:35 ` spop at gcc dot gnu.org
2015-03-17 19:05 ` law at redhat dot com
2015-03-17 20:15 ` spop at gcc dot gnu.org
2015-03-24 13:47 ` law at redhat dot com
2015-03-24 16:49 ` spop at gcc dot gnu.org
2015-03-25 23:26 ` spop at gcc dot gnu.org
2015-03-25 23:43 ` spop at gcc dot gnu.org
2015-10-28  9:01 ` yroux at gcc dot gnu.org

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