make the vector conversion magic handle multiple results.

make the vector conversion magic handle multiple results.
We now compile test2/test3 to:

_test2:
	## InlineAsm Start
	set %xmm0, %xmm1
	## InlineAsm End
	addps	%xmm1, %xmm0
	ret
_test3:
	## InlineAsm Start
	set %xmm0, %xmm1
	## InlineAsm End
	paddd	%xmm1, %xmm0
	ret

as expected.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50389 91177308-0d34-0410-b5e6-96231b3b80d8