[LLVMdev] Moving AVX Upstream

[David Greene]

Hey everyone,

I'm at the point with our local AVX tree that I'm ready to move some
stuff upstream.  We've got most of the basic stuff implemented.  The
more esoteric stuff still has to be done.

Because the more esoteric stuff might require some extensive changes to
the existing AVX infrastructure, I suspect there might be quite a bit
of church until we get things stabilized.

Due to that, I'm proposing we create an "avx" branch so I can push changes
upstream, get feedback, etc. without disturbing everyone else too much.
I would make changes incrementally, substituting an AVX definition of
existing SSE instructions and removing them from X86InstrSSE.td at the
same time.  That way we'll know when I've broken something.

Then when it's ready we can move the whole bunch over at once.

Does this sound reasonable, or do people prefer I merge to trunk?  Merging
to trunk will expose changes to more testing but could also cause a lot of
pain for people.  These are really EXTENSIVE changes to the x86 .td files
and there could be more extensive changes in the future as I write some of
the more complicated patterns.

If a branch is preferable, can we get that created?  Will commits to the 
branch go to the -commits list?  It would be even better if -commits 
subject lines could be tagged with "[avx]" or something.  What was the
precedure for the use-diet branch?

                              -Dave