[PATCH] fix a test that has no checks

[Chandler Carruth]

LGTM. Minor comment below.

================
Comment at: test/CodeGen/X86/vec_fneg.ll:8
@@ +7,3 @@
+; CHECK-LABEL: t1:
+; CHECK: xorps	{{.*}}LCPI0_0{{.*}}, %xmm0
+; CHECK-NEXT: retl
----------------
I suspect you're going to have trouble getting this to portably match. I would use a triple such as the bare metal 'x86_64-unknown-unknown' one to get a more stable pattern.

What we really should do is add comprehensive verbose asm comments that expand constant pool operands in the comment so that we can file check them in-line.

You can see some of how to do this with my changes to X86MCInstLower.cpp for comments on PSHUFB instructions if your interested... But it'll be somewhat complex. Clearly no need to do that for this patch.

http://reviews.llvm.org/D4812