diff --git a/include/llvm/Support/SlowOperationInformer.h b/include/llvm/Support/SlowOperationInformer.h
index 80ece41834f..da6bcbbc618 100644
--- a/include/llvm/Support/SlowOperationInformer.h
+++ b/include/llvm/Support/SlowOperationInformer.h
@@ -33,6 +33,7 @@
 
 #include <string>
 #include <cassert>
+#include "llvm/Support/DataTypes.h"
 
 namespace llvm {
   class SlowOperationInformer {