diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 279c4be..7f441b0 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -395,8 +395,12 @@
   } else if (const MDNode *MD = dyn_cast<MDNode>(In)) {
     if (MD->isFunctionLocal()) {
       SmallVector<Value*, 4> Elts;
-      for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i)
-        Elts.push_back(RemapOperand(MD->getOperand(i), ValueMap));
+      for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) {
+        if (MD->getOperand(i))
+          Elts.push_back(RemapOperand(MD->getOperand(i), ValueMap));
+        else
+          Elts.push_back(NULL);
+      }
       Result = MDNode::get(In->getContext(), Elts.data(), MD->getNumOperands());
     } else {
       Result = const_cast<Value*>(In);