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[Bug rtl-optimization/42889] [4.5 Regression] "-fcompare-debug failure (length)" with "-O1 -fgcse"
- From: "steven at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 28 Jan 2010 13:53:04 -0000
- Subject: [Bug rtl-optimization/42889] [4.5 Regression] "-fcompare-debug failure (length)" with "-O1 -fgcse"
- References: <bug-42889-14164@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from steven at gcc dot gnu dot org 2010-01-28 13:53 -------
The patch of comment #9 is a hack that doesn't solve anything. There are loads
of other passes that may inadvertedly trigger a fast DCE if only a DEBUG_INSN
is modified and needs to be rescanned.
IMHO the only "proper" fix would be to teach DF not to run DCE (and any other
DF-problem other than scan) if only DEBUG_INSNs are modified.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42889