RFC: AVX Intrinsics

Where would people like me to put AVX intrinsic definitions?

I could put them in the current IntrinsicsX86.td or put them
in a new file. We've called it IntrinsicsX86AVX.td. We put ours
in a separate file to avoid upstream conflicts but now that we're
getting ready to merge our stuff up we'd like the LLVM community's
opinion on where it should go.



IntrinsicsX86AVX.td seems reasonable to me.