diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index edc5b8c..023848a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1112,6 +1112,7 @@
   case ISD::CopyToReg:     return "CopyToReg";
   case ISD::CopyFromReg:   return "CopyFromReg";
   case ISD::ImplicitDef:   return "ImplicitDef";
+  case ISD::UNDEF:         return "undef";
 
   case ISD::ADD:    return "add";
   case ISD::SUB:    return "sub";