Implement splitting support for store, allowing us to compile:

	%f8 = type <8 x float>

define void @test_f8(%f8* %P, %f8* %Q, %f8* %S) {
	%p = load %f8* %P		; <%f8> [#uses=1]
	%q = load %f8* %Q		; <%f8> [#uses=1]
	%R = add %f8 %p, %q		; <%f8> [#uses=1]
	store %f8 %R, %f8* %S
	ret void
}

into:

_test_f8:
	movaps	16(%rdi), %xmm0
	addps	16(%rsi), %xmm0
	movaps	(%rdi), %xmm1
	addps	(%rsi), %xmm1
	movaps	%xmm0, 16(%rdx)
	movaps	%xmm1, (%rdx)
	ret

llvm-svn: 44725