[PATCH] [AArch64] Fix a bug generating incorrect instruction when building small vector.

[Tim Northover]

Actually, the more I think about that .ll file the more I worry that it's really showing a bug in DAGCombiner. It just happened to be the first AND-elision code I spotted that I thought I could exploit.

I think the point still stands though: these nodes can come from anywhere and we have to deal with them properly.

Cheers.

Tim.

http://reviews.llvm.org/D4385