[PATCH] Fix -march=athlon-tbird bug WRT SSE

[Kelley Cook]

 > 2005-07-28 David O'Brien <obrien@FreeBSD.org>

>	* config/i386/i386.h: Athlon-tbird does not have SSE support.

Personally, I would think that completely dropping the "athlon-tbird", "athlon-4", "k8",
"athlon-mp", "opteron", and "athlon-fx" aliases would make more sense as they don't add 
anything useful to GCC.

For a specific example the Athlon rev B. (aka Thunderbird) was just a process shrink of 
the original Athlon that the doubled the cache size and came on a PGA instead of a slot 
card.  GCC doesn't use cache size in any of its calculations while clearly packaging and 
trace size aren't relevant.

This would leave "athlon", "athlon-xp", "x86-64", and "athlon64" in the two family trees.

Athlon is the original instruction set.

Athlon-xp is Athlon + SSE

Athlon64 is the K8 chip, which is AMD's current implementation of x86-64 (which includes 3DNow!)

Finally "x86-64" remains the generic x86-64 which includes SSE2, yet neither SSE3 or 3DNow!, and 
therefore runs on either AMD original or Intel's copied implementation of x86-64.

Note that there are no Xeon nor Celeron references on the Intel side.