diff --git a/libcxx/include/__exception/exception.h b/libcxx/include/__exception/exception.h
index f7dab6e83ad14..161cc49979e4a 100644
--- a/libcxx/include/__exception/exception.h
+++ b/libcxx/include/__exception/exception.h
@@ -48,7 +48,7 @@ class exception { // base of all library exceptions
     __data_._DoFree = true;
   }
 
-  exception(exception const&) _NOEXCEPT {}
+  exception(exception const&) _NOEXCEPT : __data_() {}
 
   exception& operator=(exception const&) _NOEXCEPT { return *this; }