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Re: [PATCH, i386]: Generate xlat insn

From: Michael Matz <matz at suse dot de>
To: Richard Guenther <richard dot guenther at gmail dot com>
Cc: Uros Bizjak <ubizjak at gmail dot com>, Paolo Bonzini <bonzini at gnu dot org>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Jakub Jelinek <jakub at redhat dot com>
Date: Mon, 24 Sep 2007 17:25:23 +0200 (CEST)
Subject: Re: [PATCH, i386]: Generate xlat insn
References: <5787cf470709240150y67b6f20at9ab39c695e391470@mail.gmail.com> <46F77CF5.2070505@gnu.org> <5787cf470709240519u704820d4o912863a5403d87b6@mail.gmail.com> <84fc9c000709240624w3b79bcd7ne751fef0d69cf7f1@mail.gmail.com>

Hi,

On Mon, 24 Sep 2007, Richard Guenther wrote:

> > I very much doubt that it is worth to generate this insn. OTOH, if we 
> > conditionalize this to -Os, there will be at least a way to generate 
> > it.
> 
> Maybe this should be done post-reload only to avoid the register 
> constraining?

Indeed.  But even then only for -Os.  E.g. for AMD xlat is a vectorpath 
insn, unlike movzb, so it requires considerably more resources (even 
though the latency is the same).

Ciao,
Michael.

References:
- [PATCH, i386]: Generate xlat insn
  - From: Uros Bizjak
- Re: [PATCH, i386]: Generate xlat insn
  - From: Paolo Bonzini
- Re: [PATCH, i386]: Generate xlat insn
  - From: Uros Bizjak
- Re: [PATCH, i386]: Generate xlat insn
  - From: Richard Guenther

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