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[Bug tree-optimization/19038] [4.0 Regression] out-of ssa causing loops to have more than one BB
- 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: 23 Dec 2004 16:00:54 -0000
- Subject: [Bug tree-optimization/19038] [4.0 Regression] out-of ssa causing loops to have more than one BB
- References: <20041216155140.19038.dje@gcc.gnu.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From steven at gcc dot gnu dot org 2004-12-23 16:00 -------
s/fixing/papering over/ in the previous comment ;-)
This appears to be a problem with loop-closed ssa form, but I don't
quite understand it yet. But we should fix this on trees no matter
what, we don't need another RTL pass.
But 12.5%, wow! Making this a "normal" bug (not `enhancement') and
upgrading to P1. We really shoud fix this for GCC 4.0. If not for
performance then for the just completely broken idea that we turn a
simple 1 BB loop into a complex multiple-BBs loop. I'm quite sure
that this hurts a lot more than just SMS. (Actually, that is what
that 12.5% shows, of course.)
--
What |Removed |Added
----------------------------------------------------------------------------
Severity|minor |normal
Priority|P2 |P1
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19038