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[Bug rtl-optimization/44838] [4.6 regression] RTL loop unrolling causes FAIL: gcc.dg/pr39794.c
- From: "matz at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 7 Jul 2010 11:15:33 -0000
- Subject: [Bug rtl-optimization/44838] [4.6 regression] RTL loop unrolling causes FAIL: gcc.dg/pr39794.c
- References: <bug-44838-682@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #25 from matz at gcc dot gnu dot org 2010-07-07 11:15 -------
Due to SSA form the alias information reflects dependencies only between
accesses as if it ignores back edges. Hence any transformation that
transforms a back edge into a forward edge, or moves code over back edges
needs to do adjustment to the alias info (effectively doing something like
PHI translation, or making the alias info simply more imprecise). Hmpf.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44838