diff --git a/lib/Target/PTX/PTXParamManager.h b/lib/Target/PTX/PTXParamManager.h
index 32342f7c2c4..92e7728b4f8 100644
--- a/lib/Target/PTX/PTXParamManager.h
+++ b/lib/Target/PTX/PTXParamManager.h
@@ -17,6 +17,7 @@
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
+#include <string>
 
 namespace llvm {