diff --git a/llvm/lib/Target/X86/README.txt b/llvm/lib/Target/X86/README.txt
index 1c227d3fd140..0cf645c7a8f1 100644
--- a/llvm/lib/Target/X86/README.txt
+++ b/llvm/lib/Target/X86/README.txt
@@ -655,3 +655,7 @@ call _foo
 
 Obviously it would have been better for the first mov (or any op) to store
 directly %esp[0] if there are no other uses.
+
+//===---------------------------------------------------------------------===//
+
+Add more vector shuffle special cases using unpckhps and unpcklps.
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 4e209e4554e0..540fc11c1ebc 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -2329,7 +2329,10 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
         return DAG.getNode(ISD::VECTOR_SHUFFLE, VT, V1,
                            DAG.getNode(ISD::UNDEF, V1.getValueType()),
                            PermMask);
-    } else if (NumElems == 2 || X86::isSHUFPMask(PermMask.Val)) {
+    } else if (NumElems == 2) {
+      // All v2f64 cases are handled.
+      return SDOperand();
+    } else if (X86::isSHUFPMask(PermMask.Val)) {
       SDOperand Elt = PermMask.getOperand(0);
       if (cast<ConstantSDNode>(Elt)->getValue() >= NumElems) {
         // Swap the operands and change mask.