x86/MMX/SSE shift by immediate

Richard Henderson rth@redhat.com
Thu Jan 15 01:12:00 GMT 2004


On Wed, Jan 14, 2004 at 05:03:36PM -0800, Stuart Hastings wrote:
> Does this look plausible (IANA x86 expert ;-) ?
> 
> { target pentium-mmx-*-* pentium2-*-* winchip*-*-* c3*-*-* athlon*-*-* 
> k[68]*-*-* x86_64-*-* } for MMX
> { target pentium3-*-* k[68]*-*-* x86_64-*-* } for SSE
> { target pentium4-*-* k8*-*-* x86_64-*-* } for SSE2

No.  Most folks just type configure, which won't come up with all
these exotic names.  Indeed, config.guess is going to choose i686
(not listed) virtually all of the time with hardware produced in
the last 4 years.

If we're generating cmov just because -msse is set, then that
is a bug.  We shouldn't be generating those insns without the
appropriate -march argument.


r~



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