diff --git a/clang/lib/CodeGen/Mangle.cpp b/clang/lib/CodeGen/Mangle.cpp
index 427cc76646b4b6cc8a641eb9912f1948e322c5b0..cd97b5d916c6bc5f6c5042799cc0ac850ff6d5af 100644
--- a/clang/lib/CodeGen/Mangle.cpp
+++ b/clang/lib/CodeGen/Mangle.cpp
@@ -219,8 +219,8 @@ void CXXNameMangler::manglePrefix(const DeclContext *DC) {
   //           ::= # empty
   //           ::= <substitution>
   // FIXME: We only handle mangling of namespaces and classes at the moment.
-  if (DC->getParent() != DC)
-    manglePrefix(DC);
+  if (!DC->getParent()->isTranslationUnit())
+    manglePrefix(DC->getParent());
 
   if (const NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(DC))
     mangleSourceName(Namespace->getIdentifier());