diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
index dbb0be410a8..b94e8c76510 100644
--- a/include/llvm/Target/TargetLowering.h
+++ b/include/llvm/Target/TargetLowering.h
@@ -185,6 +185,21 @@ public:
   /// legalization.
   virtual bool shouldSplitVectorElementType(EVT /*VT*/) const { return false; }
 
+  // There are two general methods for expanding a BUILD_VECTOR node:
+  //  1. Use SCALAR_TO_VECTOR on the defined scalar values and then shuffle
+  //     them together.
+  //  2. Build the vector on the stack and then load it.
+  // If this function returns true, then method (1) will be used, subject to
+  // the constraint that all of the necessary shuffles are legal (as determined
+  // by isShuffleMaskLegal). If this function returns false, then method (2) is
+  // always used. The vector type, and the number of defined values, are
+  // provided.
+  virtual bool
+  shouldExpandBuildVectorWithShuffles(EVT /* VT */,
+                                      unsigned DefinedValues) const {
+    return DefinedValues < 3;
+  }
+
   /// Return true if integer divide is usually cheaper than a sequence of
   /// several shifts, adds, and multiplies for this target.
   bool isIntDivCheap() const { return IntDivIsCheap; }
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 608de82265a..853bae7b5bd 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/CodeGen/Analysis.h"
@@ -1889,7 +1890,15 @@ SDValue SelectionDAGLegalize::ExpandBUILD_VECTOR(SDNode *Node) {
                        false, false, false, Alignment);
   }
 
-  if (!MoreThanTwoValues) {
+  SmallSet<SDValue, 16> DefinedValues;
+  for (unsigned i = 0; i < NumElems; ++i) {
+    if (Node->getOperand(i).getOpcode() == ISD::UNDEF)
+      continue;
+    DefinedValues.insert(Node->getOperand(i));
+  }
+
+  if (!MoreThanTwoValues &&
+    TLI.shouldExpandBuildVectorWithShuffles(VT, DefinedValues.size())) {
     SmallVector<int, 8> ShuffleVec(NumElems, -1);
     for (unsigned i = 0; i < NumElems; ++i) {
       SDValue V = Node->getOperand(i);