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[Bug middle-end/29256] [4.2 regression] loop performance regression
- From: "rakdver 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 Sep 2006 14:21:25 -0000
- Subject: [Bug middle-end/29256] [4.2 regression] loop performance regression
- References: <bug-29256-12262@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #12 from rakdver at gcc dot gnu dot org 2006-09-28 14:21 -------
(In reply to comment #11)
> (In reply to comment #9)
> > Oh, didn't I fix this? See PR26726.
> This is unrelated to that as the trees produced is defined but just looks weird
> and really the one IV selection is messed up. It should have chosen two IVs
> for this loop instead of just one.
> Actually unrolling is not need to produced the bad code:
> .L2:
> lwz 0,0(9)
> stwx 0,11,9
> addi 9,9,4
> bdnz .L2
> I bet a beer that loop.c actually fixed this crap up before.
I am bad at reading ppc assembler; could you please explain what exactly is
wrong with the code you present?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29256