diff --git a/include/llvm/ADT/Optional.h b/include/llvm/ADT/Optional.h
index aa43f552d50..06e5af073f4 100644
--- a/include/llvm/ADT/Optional.h
+++ b/include/llvm/ADT/Optional.h
@@ -28,7 +28,7 @@ namespace llvm {
 template<typename T>
 class Optional {
   T x;
-  unsigned hasVal : 1;
+  bool hasVal;
 public:
   explicit Optional() : x(), hasVal(false) {}
   Optional(const T &y) : x(y), hasVal(true) {}