diff --git a/qrexec-lib/Makefile b/qrexec-lib/Makefile
index c9b5fe7..c033718 100644
--- a/qrexec-lib/Makefile
+++ b/qrexec-lib/Makefile
@@ -1,5 +1,5 @@
 CC=gcc
-CFLAGS+=-I. -g -Wall -Wextra -Werror -pie -fPIC
+CFLAGS+=-I. -g -O2 -Wall -Wextra -Werror -pie -fPIC
 XENLIBS=-lxenctrl -lxenstore -lvchan
 COMMONIOALL=ioall.o
 SO_VER=1