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Re: [3.0] Re: egcs/gcc ChangeLog config/i386/i386.md
- To: Richard Henderson <rth at redhat dot com>, "hubicka at gcc dot gnu dot org" <hubicka at gcc dot gnu dot org>
- Subject: Re: [3.0] Re: egcs/gcc ChangeLog config/i386/i386.md
- From: Mark Mitchell <mark at codesourcery dot com>
- Date: Fri, 05 Oct 2001 11:28:01 -0700
- cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
--On Friday, October 05, 2001 11:18:46 AM -0700 Richard Henderson
<rth@redhat.com> wrote:
> On Thu, Oct 04, 2001 at 02:20:39PM -0000, hubicka@gcc.gnu.org wrote:
>> * i386.c (setcc peep2): Do not use clobber of flags.
>
> This severely pessimizes the PII core.
>
> The "xor reg,reg" is special in that it sets a "register clear"
> flag that avoids a partial register stall with the subsequent
> setcc. Unfortunately, "mov $0,reg" does not have the same effect.
Fascinating.
> I think the following is in order. Bootstrapped on i686-linux
> with -march=k6 in BOOT_CFLAGS.
>
> Ok, Mark?
Yes, thanks!
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com