Skip upcast, NFC

llvm-svn: 226514
diff --git a/llvm/lib/Transforms/Utils/ValueMapper.cpp b/llvm/lib/Transforms/Utils/ValueMapper.cpp
index 4033ccb..89f619b 100644
--- a/llvm/lib/Transforms/Utils/ValueMapper.cpp
+++ b/llvm/lib/Transforms/Utils/ValueMapper.cpp
@@ -213,7 +213,7 @@
   assert(Node->isDistinct() && "Expected distinct node");
 
   // Create the node first so it's available for cyclical references.
-  MDNode *NewMD = MDNode::replaceWithDistinct(cloneMDNode(Node));
+  UniquableMDNode *NewMD = MDNode::replaceWithDistinct(cloneMDNode(Node));
   mapToMetadata(VM, Node, NewMD);
 
   // Fix the operands.