diff --git a/lib/Analysis/DebugInfo.cpp b/lib/Analysis/DebugInfo.cpp
index aa012ef8bcb..f1ad08aefab 100644
--- a/lib/Analysis/DebugInfo.cpp
+++ b/lib/Analysis/DebugInfo.cpp
@@ -213,7 +213,7 @@ void DIDerivedType::replaceAllUsesWith(DIDescriptor &D) {
   if (isNull())
     return;
 
-  assert (D.isNull() && "Can not replace with null");
+  assert (!D.isNull() && "Can not replace with null");
   getGV()->replaceAllUsesWith(D.getGV());
   getGV()->eraseFromParent();
 }