[llvm] r214992 - Fix a test that has no checks.

[Sanjay Patel]

Author: spatel
Date: Wed Aug  6 15:45:30 2014
New Revision: 214992

URL: http://llvm.org/viewvc/llvm-project?rev=214992&view=rev
Log:
Fix a test that has no checks.

X86 doesn't have fneg, so check for xor.

Differential Revision: http://reviews.llvm.org/D4812

Modified:
    llvm/trunk/test/CodeGen/X86/vec_fneg.ll

Modified: llvm/trunk/test/CodeGen/X86/vec_fneg.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vec_fneg.ll?rev=214992&r1=214991&r2=214992&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vec_fneg.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vec_fneg.ll Wed Aug  6 15:45:30 2014
@@ -1,11 +1,23 @@
-; RUN: llc < %s -march=x86 -mattr=+sse2
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mcpu=corei7 | FileCheck %s
 
+; FNEG is defined as subtraction from -0.0.
+
+; This test verifies that we use an xor with a constant to flip the sign bits; no subtraction needed.
 define <4 x float> @t1(<4 x float> %Q) {
-        %tmp15 = fsub <4 x float> < float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00 >, %Q
-	ret <4 x float> %tmp15
+; CHECK-LABEL: t1:
+; CHECK: xorps	{{.*}}LCPI0_0{{.*}}, %xmm0
+; CHECK-NEXT: retq
+        %tmp = fsub <4 x float> < float -0.000000e+00, float -0.000000e+00, float -0.000000e+00, float -0.000000e+00 >, %Q
+	ret <4 x float> %tmp
 }
 
+; This test verifies that we generate an FP subtraction because "0.0 - x" is not an fneg.
 define <4 x float> @t2(<4 x float> %Q) {
-        %tmp15 = fsub <4 x float> zeroinitializer, %Q
-	ret <4 x float> %tmp15
+; CHECK-LABEL: t2:
+; CHECK: xorps	%[[X:xmm[0-9]+]], %[[X]]
+; CHECK-NEXT: subps	%xmm0, %[[X]]
+; CHECK-NEXT: movaps	%[[X]], %xmm0
+; CHECK-NEXT: retq
+        %tmp = fsub <4 x float> zeroinitializer, %Q
+	ret <4 x float> %tmp
 }