diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index c8097a0..33da5e4 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -789,9 +789,13 @@
       unsigned Size = Record.size();
       SmallVector<MDNode *, 8> Elts;
       for (unsigned i = 0; i != Size; ++i) {
-        Value *MD = MDValueList.getValueFwdRef(Record[i]);
-        if (MDNode *B = dyn_cast_or_null<MDNode>(MD))
-          Elts.push_back(B);
+        if (Record[i] == ~0U)
+          Elts.push_back(NULL);
+        else {
+          Value *MD = MDValueList.getValueFwdRef(Record[i]);
+          if (MDNode *B = dyn_cast_or_null<MDNode>(MD))
+            Elts.push_back(B);
+        }
       }
       Value *V = NamedMDNode::Create(Context, Name.str(), Elts.data(),
                                      Elts.size(), TheModule);
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index c78a30e..ce9036b 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -540,7 +540,7 @@
         if (NMD->getOperand(i))
           Record.push_back(VE.getValueID(NMD->getOperand(i)));
         else
-          Record.push_back(0);
+          Record.push_back(~0U);
       }
       Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
       Record.clear();
diff --git a/lib/Bitcode/Writer/ValueEnumerator.cpp b/lib/Bitcode/Writer/ValueEnumerator.cpp
index 861de84..c409c20 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -223,7 +223,8 @@
   
   if (const NamedMDNode *N = dyn_cast<NamedMDNode>(MD)) {
     for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
-      EnumerateValue(N->getOperand(i));
+      if (MDNode *E = N->getOperand(i))
+        EnumerateValue(E);
     MDValues.push_back(std::make_pair(MD, 1U));
     MDValueMap[MD] = Values.size();
     return;