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Re: Fix PR 44576: avoid huge compile times in compute_miss_rate
- From: Richard Guenther <richard dot guenther at gmail dot com>
- To: Christian Borntraeger <borntraeger at de dot ibm dot com>
- Cc: Gcc Patch List <gcc-patches at gcc dot gnu dot org>, uweigand at de dot ibm dot com, Changpeng dot Fang at amd dot com
- Date: Mon, 28 Jun 2010 12:04:23 +0200
- Subject: Re: Fix PR 44576: avoid huge compile times in compute_miss_rate
- References: <4C28527C.4070406@de.ibm.com>
On Mon, Jun 28, 2010 at 9:42 AM, Christian Borntraeger
<borntraeger@de.ibm.com> wrote:
> This patches fixes the huge compile times in compute_miss_rate in
> the prefetch pass.
>
> This patch does not fix the other code size or compile time problems
> that are tracked in PR44688.
>
>
>
> 2010-06-28 ?Christian Borntraeger ?<borntraeger@de.ibm.com>
>
> ? ? ? ?PR middle-end/44576
> ? ? ? ?* tree-ssa-loop-prefetch.c (PREFETCH_MAX_REFS_PER_LOOP): New.
> ? ? ? ?* (loop_prefetch_arrays): Do not prefetch if the loop contains
> ? ? ? ?too many memory references.
>
>
> OK to apply?
No. Please instead do some profiling work and take a stab at
improving the algorithm instead. There are several places which
are quadratic in compile-time in gcc, so I don't see why prefetching
should be particular bad.
Richard.