diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 7b878688df6..10daa31b6a3 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -7261,8 +7261,19 @@ SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) {
       }
 
       EVT VT = LHSOp.getValueType();
-      assert(RHSOp.getValueType() == VT &&
-             "SimplifyVBinOp with different BUILD_VECTOR element types");
+      EVT RVT = RHSOp.getValueType();
+      if (RVT != VT) {
+        // Integer BUILD_VECTOR operands may have types larger than the element
+        // size (e.g., when the element type is not legal).  Prior to type
+        // legalization, the types may not match between the two BUILD_VECTORS.
+        // Truncate one of the operands to make them match.
+        if (RVT.getSizeInBits() > VT.getSizeInBits()) {
+          RHSOp = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, RHSOp);
+        } else {
+          LHSOp = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), RVT, LHSOp);
+          VT = RVT;
+        }
+      }
       SDValue FoldOp = DAG.getNode(N->getOpcode(), LHS.getDebugLoc(), VT,
                                    LHSOp, RHSOp);
       if (FoldOp.getOpcode() != ISD::UNDEF &&
diff --git a/test/CodeGen/ARM/vector-DAGCombine.ll b/test/CodeGen/ARM/vector-DAGCombine.ll
index 81bdc44863b..1a97982eb0a 100644
--- a/test/CodeGen/ARM/vector-DAGCombine.ll
+++ b/test/CodeGen/ARM/vector-DAGCombine.ll
@@ -123,3 +123,13 @@ define void @orVec(<3 x i8>* %A) nounwind {
   ret void
 }
 
+; The following test was hitting an assertion in the DAG combiner when
+; constant folding the multiply because the "sext undef" was translated to
+; a BUILD_VECTOR with i32 0 operands, which did not match the i16 operands
+; of the other BUILD_VECTOR.
+define i16 @foldBuildVectors() {
+  %1 = sext <8 x i8> undef to <8 x i16>
+  %2 = mul <8 x i16> %1, <i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255>
+  %3 = extractelement <8 x i16> %2, i32 0
+  ret i16 %3
+}