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

[Tim Northover]

Hi Kevin,

I think the function is correct now, but that second test is pretty much useless if it really is relying on a bug in the DAG-combiner. As soon as someone fixes that it'll no longer even exercise the code it's supposed to.

I've got one or two ideas to improve this function with refactoring, though, so I think you should probably just commit and then I can take a look afterwards.

So LGTM! Thanks for working on this for so long (and being patient at the beginning).

Cheers.

Tim.

http://reviews.llvm.org/D4385