diff --git a/include/llvm/LinkTimeOptimizer.h b/include/llvm/LinkTimeOptimizer.h
index de48aa7f2ea..eea0093e80f 100644
--- a/include/llvm/LinkTimeOptimizer.h
+++ b/include/llvm/LinkTimeOptimizer.h
@@ -45,7 +45,8 @@ namespace llvm {
     LTOExternalLinkage, // Externally visible function
     LTOLinkOnceLinkage, // Keep one copy of named function when linking (inline)
     LTOWeakLinkage,     // Keep one copy of named function when linking (weak)
-    LTOInternalLinkage  // Rename collisions when linking (static functions)
+    LTOInternalLinkage, // Rename collisions when linking (static functions)
+    LTOCommonLinkage    // tentative definitions (usually equivalent to weak)
   };
 
   enum LTOVisibilityTypes {