Emit target specific nodes to handle splats starting at zero indicies

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113055 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 95dbb61766874a5c21d35d81c80928364f664cc7..f7b8100f70e805ae04737279852f7c02779ae472 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -5470,10 +5470,17 @@ X86TargetLowering::LowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG) const {
 
   // FIXME: pshufb, blends, shifts.
   if (VT.getVectorNumElements() == 2 ||
-      ShuffleVectorSDNode::isSplatMask(&M[0], VT) ||
       isPALIGNRMask(M, VT, Subtarget->hasSSSE3()))
     return Op;
 
+  if (ShuffleVectorSDNode::isSplatMask(&M[0], VT) &&
+      SVOp->getSplatIndex() == 0 && V2IsUndef) {
+    if (VT == MVT::v2f64)
+      return getTargetShuffleNode(X86ISD::UNPCKLPD, dl, VT, V1, V1, DAG);
+    if (VT == MVT::v2i64)
+      return getTargetShuffleNode(X86ISD::PUNPCKLQDQ, dl, VT, V1, V1, DAG);
+  }
+
   if (isPSHUFHWMask(M, VT))
     return getTargetShuffleNode(X86ISD::PSHUFHW, dl, VT, V1,
                                 X86::getShufflePSHUFHWImmediate(SVOp),