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Re: 9 Nov 06 notes from GCC improvement for Itanium conference call
- From: Dorit Nuzman <DORIT at il dot ibm dot com>
- To: Vladimir Makarov <vmakarov at redhat dot com>
- Cc: abel at ispras dot ru, Ayal Zaks <zaks at il dot ibm dot com>, gcc at gcc dot gnu dot org, mksmith at gelato dot org, Vladimir Yanovsky <yanov at il dot ibm dot com>, Vladimir Yanovsky <volodyan at gmail dot com>
- Date: Wed, 22 Nov 2006 14:37:00 +0200
- Subject: Re: 9 Nov 06 notes from GCC improvement for Itanium conference call
> Vladimir Yanovsky wrote:
>
> That comment was about SMS. Last time when I tried SMS for Itanium on
> SPEC2000 a few monts ago, a lot of tests did not work. As RCSP I don't
> think we need this. It is too complicated algorithm. Mainstream
> approach is modulo scheduling. I hope people from ISP RAS will
> implement enhanced software pipleining (as part of their new insn
> scheduler) as a complimentary software pipelining algorithm for loops
> with branches.
>
> Imho the big problem of implementing software pipelining in gcc
> environment is passes working after the MS and changing the pipelined
> code. SMS is actually good for gcc because it makes register allocator
> changes (when register pressure is high) is less frequent.
> Unfortunately reload (ant other subsequent passes) does other
> transformations too (not only spilling registers when the pressure is
> high). But as Dorit wrote in her email SMS works well at least for PPC.
>
just for the record - I was actually referring to the Cell SPU (which is
not a PPC architecture).
dorit
> >
> >> We also plan to fix swing modulo scheduling to make it work on ia64
> >> and improve it by propagating data dependency information to RTL. We
> >> plan to discuss this project on the GCC mailing list in a few weeks.
> >
> >
> >
>
>