diff --git a/tensorflow/g3doc/how_tos/adding_an_op/index.md b/tensorflow/g3doc/how_tos/adding_an_op/index.md
index 767364b16df..6947ceec448 100644
--- a/tensorflow/g3doc/how_tos/adding_an_op/index.md
+++ b/tensorflow/g3doc/how_tos/adding_an_op/index.md
@@ -139,7 +139,7 @@ to compile your Op into a dynamic library.
 ```bash
 TF_INC=$(python -c 'import tensorflow as tf; print(tf.sysconfig.get_include())')
 
-g++ -std=c++11 -shared zero_out.cc -o zero_out.so -fPIC -I $TF_INC
+g++ -std=c++11 -shared zero_out.cc -o zero_out.so -fPIC -I $TF_INC -O2
 ```
 
 On Mac OS X, the additional flag "-undefined dynamic_lookup" is required when