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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/56264] [4.8 Regression] ICE in check_loop_closed_ssa_use, at  tree-ssa-loop-manip.c:557
Date: Mon, 11 Feb 2013 10:28:00 -0000	[thread overview]
Message-ID: <bug-56264-4-PH7FXB18EN@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-56264-4@http.gcc.gnu.org/bugzilla/>


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56264

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> 2013-02-11 10:27:56 UTC ---
I would guess that originally cfg-cleanup caused basic-blocks to leak
outside a loop, thus at most exposing new use sites.  With discovering
new loops we may both wreck that scheme (loop depth may not change but
blocks still leak) and fail to recognize use-blocks of defs that changed
loop ownership.

Fix_loop_structure could return the number of newly discovered loops,
indicating that the whole function needs to be re-scanned (still not accounting
for weird loop tree hierarchy changes, but those shouldn't be caused by
transformations cfgcleanup does).

Testing a patch.


  parent reply	other threads:[~2013-02-11 10:28 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-09 12:09 [Bug tree-optimization/56264] New: " antoine.balestrat at gmail dot com
2013-02-09 12:15 ` [Bug tree-optimization/56264] " mpolacek at gcc dot gnu.org
2013-02-09 13:37 ` [Bug tree-optimization/56264] [4.8 Regression] " mpolacek at gcc dot gnu.org
2013-02-10 12:21 ` rguenth at gcc dot gnu.org
2013-02-11 10:00 ` rguenth at gcc dot gnu.org
2013-02-11 10:28 ` rguenth at gcc dot gnu.org [this message]
2013-02-11 15:08 ` rguenth at gcc dot gnu.org
2013-02-11 15:10 ` rguenth at gcc dot gnu.org

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