diff --git a/tools/bugpoint/ListReducer.h b/tools/bugpoint/ListReducer.h
index 0ad24065cf3..07c0a2d1dd1 100644
--- a/tools/bugpoint/ListReducer.h
+++ b/tools/bugpoint/ListReducer.h
@@ -16,6 +16,7 @@
 #define BUGPOINT_LIST_REDUCER_H
 
 #include <vector>
+#include <iostream>
 
 namespace llvm {