diff --git a/llvm/include/Support/CommandLine.h b/llvm/include/Support/CommandLine.h
index 410361797a5b733b0d5f8e43f1519dcc8297623e..dcd3b5ba511ee025096d059bb9f683fcfb732093 100644
--- a/llvm/include/Support/CommandLine.h
+++ b/llvm/include/Support/CommandLine.h
@@ -642,7 +642,8 @@ class opt_storage {
 
   void check() {
     assert(Location != 0 && "cl::location(...) not specified for a command "
-           "line option with external storage!");
+           "line option with external storage, "
+           "or cl::init specified before cl::location()!!");
   }
 public:
   opt_storage() : Location(0) {}