diff --git a/lib/Transforms/Scalar/PRE.cpp b/lib/Transforms/Scalar/PRE.cpp
index f8752336b2e..15884b6c761 100644
--- a/lib/Transforms/Scalar/PRE.cpp
+++ b/lib/Transforms/Scalar/PRE.cpp
@@ -34,6 +34,7 @@
 #include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/hash_set"
+#include "llvm/ADT/hash_map"
 using namespace llvm;
 
 namespace {