diff --git a/include/llvm/IR/Metadata.h b/include/llvm/IR/Metadata.h
index 5590bc54881..8c2e78ad4b1 100644
--- a/include/llvm/IR/Metadata.h
+++ b/include/llvm/IR/Metadata.h
@@ -48,10 +48,10 @@ class Metadata {
 
 protected:
   /// \brief Active type of storage.
-  enum StorageType { Uniqued, Distinct, Temporary };
+  enum StorageType : unsigned char { Uniqued, Distinct, Temporary };
 
   /// \brief Storage flag for non-uniqued, otherwise unowned, metadata.
-  unsigned Storage : 2;
+  StorageType Storage : 2;
   // TODO: expose remaining bits to subclasses.
 
   unsigned short SubclassData16;