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[Bug tree-optimization/56264] [4.8 Regression] ICE in check_loop_closed_ssa_use, at tree-ssa-loop-manip.c:557
- From: "rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 11 Feb 2013 10:27:56 +0000
- Subject: [Bug tree-optimization/56264] [4.8 Regression] ICE in check_loop_closed_ssa_use, at tree-ssa-loop-manip.c:557
- Auto-submitted: auto-generated
- References: <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.