diff --git a/llvm/lib/Analysis/DataStructure/EquivClassGraphs.cpp b/llvm/lib/Analysis/DataStructure/EquivClassGraphs.cpp
index 26544ce..4aa65b2 100644
--- a/llvm/lib/Analysis/DataStructure/EquivClassGraphs.cpp
+++ b/llvm/lib/Analysis/DataStructure/EquivClassGraphs.cpp
@@ -26,6 +26,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/EquivalenceClasses.h"
 #include "llvm/ADT/STLExtras.h"
+#include <iostream>
 using namespace llvm;
 
 namespace {