Best way to compile for a 32-bit chroot on a 64-bit processor - -march=athlonxp, or -march=k8 -m32 ?

[Asfand Yar Qazi]

Hi,

What's the best way of compiling for a 32-bit chroot on a 64-bit processor?
I'm currently using '-march=athlon-xp', but I don't know if that makes best
use of all the 32-bit compatible instructions on my chip, and if the code is
best tuned to my chip.  Would '-march=k8 -m32' be better?

BTW, we're talking compiling a Gentoo 32-bit chroot environment here.

Thanks