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Re: [patch] enabling vectorization by default at -O3
- From: Mark Mitchell <mark at codesourcery dot com>
- To: Dorit Nuzman <DORIT at il dot ibm dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Ira Rosen <IRAR at il dot ibm dot com>
- Date: Thu, 13 Sep 2007 11:49:51 -0700
- Subject: Re: [patch] enabling vectorization by default at -O3
- References: <OFF0ECF488.A8736665-ONC2257354.001F3A08-C2257354.002A3B8F@il.ibm.com>
Dorit Nuzman wrote:
> SpecCPU2006 on powerpc970 shows 1.5% on specINT (mostly due to a 14%
> improvement on hmmer), and a -0.4% on specFP. This was comparing '-O3' with
> '-O3 -ftree-vectorize -maltivec'. The costmodel wasn't on, cause it is
> still undergoing some changes, and also it is not tuned yet for powerpc970,
> so I hope that with the costmodel on we'll be able to get rid of the small
> degradations we have here and there later on.
I was hoping for a bit more of an overall win. The negative result on
specFP worries me; although the overall scores are higher, it would be
nice if we could eliminate that negative.
Do any of the other optimization maintainers have a feeling about this?
Should we turn on vectorization at -O3, or are we not quite there yet?
Thanks,
--
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713