diff --git a/lib/CodeGen/AsmPrinter/DIE.h b/lib/CodeGen/AsmPrinter/DIE.h
index 3c06001686f..d8fa1f5a0e7 100644
--- a/lib/CodeGen/AsmPrinter/DIE.h
+++ b/lib/CodeGen/AsmPrinter/DIE.h
@@ -325,7 +325,9 @@ namespace llvm {
   class DIEEntry : public DIEValue {
     DIE *const Entry;
   public:
-    explicit DIEEntry(DIE *E) : DIEValue(isEntry), Entry(E) {}
+    explicit DIEEntry(DIE *E) : DIEValue(isEntry), Entry(E) {
+      assert(E && "Cannot construct a DIEEntry with a null DIE");
+    }
 
     DIE *getEntry() const { return Entry; }