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Re: Byte permutation optimization
- From: "Daniel Berlin" <dberlin at dberlin dot org>
- To: "Andi Kleen" <andi at firstfloor dot org>
- Cc: "Nils Pipenbrinck" <n dot pipenbrinck at cubic dot org>, gcc at gcc dot gnu dot org
- Date: Sun, 13 Jul 2008 12:55:50 -0400
- Subject: Re: Byte permutation optimization
- References: <48791902.2020805@cubic.org> <878ww613ih.fsf@basil.nowhere.org>
On Sun, Jul 13, 2008 at 6:29 AM, Andi Kleen <andi@firstfloor.org> wrote:
> Nils Pipenbrinck <n.pipenbrinck@cubic.org> writes:
>
>> Since the codebase is huge I have the feeling that I have overlooked
>> something. Does some kind of infrastructure to detect patterns within
>> a SSA tree already exists somewhere else?
>
> FWIW some time ago I wanted to do some other arithmetic optimization
> on expressions and didn't find a nice generic "misc transformation
> pass" or an generic pattern matcher. Probably one would need to be added.
The closest we have to misc transforms like this at the tree level is
either forwprop or reassoc
Probably better, as you say, to add a misc pattern matcher.