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Re: [autovect] [patch] vectorize reduction without specialized targetsupport
- From: Dorit Naishlos <DORIT at il dot ibm dot com>
- To: Richard Henderson <rth at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Sat, 18 Jun 2005 14:34:25 +0300
- Subject: Re: [autovect] [patch] vectorize reduction without specialized targetsupport
Richard Henderson <firstname.lastname@example.org> wrote on 15/06/2005 23:22:28:
> On Wed, Jun 15, 2005 at 11:05:54PM +0300, Dorit Naishlos wrote:
> > This scheme requires adding new tree-codes for the vector-shifts. I
> > introduced the simplest vector-shift possible - the shift amount is in
> > bytes, and is a constant (immediate value). This has to potential to be
> > easily expanded to the most efficient code, and be applicable to as
> > targets as possible.
> One change I'd prefer is that the shift count remain in bits, as with
> any other shift that gcc supports. I think that's less confusing.
ok, I committed this change to autovect, will prepare for mainline.
> (Despite the fact that both SSE and Altivec actually implement that
> shift by encoding the number of bytes into the instruction.)