Unaligned SSE Memop Support Patch

This patch adds a feature to allow SSE memops to be unaligned
on supported architectures.

Mostly I want to see if the naming is reasonable.

Supporting unaligned memops requires a bit twiddle on 10h
processors. This patch makes the assumption that the OS
sets the bit correctly.



uamem.patch (3.5 KB)

Please mention "SIMD" or "vector" in the description string in
the SubtargetFeature definition, to avoid confusion. Also, it would be
good to mention "for example, the AMD 10h" in a comment somewhere.

Otherwise, looks good to me.