Make DAGCombiner work on vector bitshifts with constant splat vectors.

llvm-svn: 204071

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 43a02fe9c7e..df8d423ab22 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -6573,6 +6573,19 @@ bool BuildVectorSDNode::isConstantSplat(APInt &SplatValue,
   return true;
 }
 
+ConstantSDNode *BuildVectorSDNode::isConstantSplat() const {
+  SDValue Op0 = getOperand(0);
+  for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
+    SDValue Opi = getOperand(i);
+    unsigned Opc = Opi.getOpcode();
+    if ((Opc != ISD::UNDEF && Opc != ISD::Constant && Opc != ISD::ConstantFP) ||
+        Opi != Op0)
+      return nullptr;
+  }
+
+  return cast<ConstantSDNode>(Op0);
+}
+
 bool BuildVectorSDNode::isConstant() const {
   for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
     unsigned Opc = getOperand(i).getOpcode();