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Re: Serious performance regression -- some tree optimizer questions
- From: Steven Bosscher <stevenb at suse dot de>
- To: gcc at gcc dot gnu dot org
- Cc: Ulrich Weigand <uweigand at de dot ibm dot com>
- Date: Sat, 18 Dec 2004 01:18:04 +0100
- Subject: Re: Serious performance regression -- some tree optimizer questions
- Organization: SUSE Labs
- References: <200412172124.iBHLOwF3010084@53v30g16.boeblingen.de.ibm.com>
On Friday 17 December 2004 22:24, Ulrich Weigand wrote:
> Hello,
>
> we've started to do some performance analysis of current GCC mainline
> on zSeries, and while in general results are promising, we've found a
> couple of serious performance regressions. The most extreme one was
> the SPECfp2000 test case mgrid -- on s390x optimized for z990, this
> test case takes about *twice* the run time with current mainline as
> it did with GCC 3.4 ...
When I last looked at mgrid for AMD64, I found -fno-tree-pre to
be very helpful.
Gr.
Steven