diff --git a/test/libm-bench.cpp b/test/libm-bench.cpp
index 5b9e139..3d4b028 100644
--- a/test/libm-bench.cpp
+++ b/test/libm-bench.cpp
@@ -1,3 +1,5 @@
+// Copyright (C) Dahua Lin, 2014. Provided under the MIT license.
+
 // Benchmark on libm functions
 
 #include <math.h>