diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp
index f5a207844b8..e302f0bf863 100644
--- a/lib/Support/Allocator.cpp
+++ b/lib/Support/Allocator.cpp
@@ -15,6 +15,7 @@
 #include "llvm/Support/Recycler.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/Streams.h"
+#include <cstring>
 
 namespace llvm {