Re: [head tinderbox] failure on amd64/amd64

From: Bruce Evans <bde_at_zeta.org.au>
Date: Fri, 29 Sep 2006 01:55:59 +1000 (EST)
On Thu, 28 Sep 2006, Ruslan Ermilov wrote:

> I.e., by default, -m32 on amd64 still tunes for k8.  I don't
> know what others think about it (perhaps it would still be
> a good idea to tune for k8 on amd64 even in the boot code),

No, speed is unimportant and tuning for Athlons generally
gives larger code (though it probably shouldn't with -Os).

However, tuning for i386 might not give smallest code.

amd64 can also execute non-i386 instructions so it could
use "arch"ing instead of tuning for Athlons.  At least bswap
would be smaller (probably not enough other instructions
to matter).  I don't know how to use non-i386 instructions
without losing tuning for i386's.

> but for now this looked a good work-around to me, and it
> definitely takes less bytes than the k8-tuned version.

Bruce
Received on Thu Sep 28 2006 - 15:28:00 UTC

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