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Re: Building for K6-2 CPU: i586 or i686?
- To: steve dot snyder at philips dot com
- Subject: Re: Building for K6-2 CPU: i586 or i686?
- From: Michael Meissner <meissner at cygnus dot com>
- Date: Wed, 20 Jun 2001 03:49:35 -0400
- Cc: gcc at gcc dot gnu dot org
- References: <0056910012731724000002L142*@MHS>
On Tue, Jun 19, 2001 at 04:23:21PM -0500, steve.snyder@philips.com wrote:
> Hello.
>
> Which compiler option generates better code for the AMD K6-2 CPU,
> -march=i586 or -march=i686?
IIRC, you don't want -march=i686, since the K6 doesn't have the conditional
move instructions that the i686 processors do.
> Please don't rub salt into my wounds by suggesting "-march=k6" as the way
> to go. I want the code to actually *run* after it's compiled. (See
> PR2676 in GNATS ("Illegal loop instruction when using -O2 -march=k6" as
> well as post http://gcc.gnu.org/ml/gcc/2001-06/msg01058.html.)
>
> Thank you.
--
Michael Meissner, Red Hat, Inc. (GCC group)
PMB 198, 174 Littleton Road #3, Westford, Massachusetts 01886, USA
Work: meissner@redhat.com phone: +1 978-486-9304
Non-work: meissner@spectacle-pond.org fax: +1 978-692-4482