diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 8deaae9..2c97d35 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2482,6 +2482,8 @@
            "Vector element count mismatch!");
     if (OpOpcode == ISD::SIGN_EXTEND || OpOpcode == ISD::ZERO_EXTEND)
       return getNode(OpOpcode, DL, VT, Operand.getNode()->getOperand(0));
+    else if (OpOpcode == ISD::UNDEF)
+      return getUNDEF(VT);
     break;
   case ISD::ZERO_EXTEND:
     assert(VT.isInteger() && Operand.getValueType().isInteger() &&
@@ -2512,6 +2514,8 @@
         OpOpcode == ISD::ANY_EXTEND)
       // (ext (zext x)) -> (zext x)  and  (ext (sext x)) -> (sext x)
       return getNode(OpOpcode, DL, VT, Operand.getNode()->getOperand(0));
+    else if (OpOpcode == ISD::UNDEF)
+      return getUNDEF(VT);
 
     // (ext (trunx x)) -> x
     if (OpOpcode == ISD::TRUNCATE) {