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[Bug tree-optimization/18595] [4.0/4.1 Regression] IV-OPTS is O(N^3)
- From: "mmitchel at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 31 Oct 2005 01:48:51 -0000
- Subject: [Bug tree-optimization/18595] [4.0/4.1 Regression] IV-OPTS is O(N^3)
- References: <bug-18595-6528@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #55 from mmitchel at gcc dot gnu dot org 2005-10-31 01:48 -------
I wouldn't worry too much about exceedingly deep loop nests. Even the
scientific code I've looked at rarely has loop nests deeper than ten -- and if
it does, optimizing the inner ten loops is probably good enough.
So, I'd suggest that we add a --param here for max-loop-nest-depth, and then
just not do this stuff on deeper nests, or ignore all the outer loops in that
case.
Is that feasible?
Marked as P4; I think we should fix this, but I don't think it needs to happen
for 4.1. I'll revise for 4.2.
--
mmitchel at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P4
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18595