diff --git a/c_runtime/Makefile.test b/c_runtime/Makefile.test
index a6e548300..e9155d47f 100644
--- a/c_runtime/Makefile.test
+++ b/c_runtime/Makefile.test
@@ -1,16 +1,19 @@
+FLAGS = -flto -O3
+//FLAGS = -g
+
 all: bosatsu_runtime.o test_out bosatsu_ext_Bosatsu_l_Predef.o bosatsu_ext_Bosatsu_l_Prog.o
 
 bosatsu_runtime.o: bosatsu_runtime.h bosatsu_runtime.c bosatsu_decls_generated.h bosatsu_generated.h
-	gcc -g -c -Wall -Werror bosatsu_runtime.c
+	gcc $(FLAGS) -c -Wall -Werror bosatsu_runtime.c
 
 bosatsu_ext_Bosatsu_l_Predef.o: bosatsu_ext_Bosatsu_l_Predef.c bosatsu_runtime.o
-	gcc -g -Wall -Werror -c bosatsu_ext_Bosatsu_l_Predef.c
+	gcc $(FLAGS) -Wall -Werror -c bosatsu_ext_Bosatsu_l_Predef.c
 
 bosatsu_ext_Bosatsu_l_Prog.o: bosatsu_ext_Bosatsu_l_Prog.c bosatsu_runtime.o
-	gcc -g -Wall -Werror -c bosatsu_ext_Bosatsu_l_Prog.c
+	gcc $(FLAGS) -Wall -Werror -c bosatsu_ext_Bosatsu_l_Prog.c
 
 test_exe: output.c bosatsu_runtime.o bosatsu_ext_Bosatsu_l_Prog.o bosatsu_ext_Bosatsu_l_Predef.o
-	gcc -g -o test_exe output.c bosatsu_runtime.o bosatsu_ext_Bosatsu_l_Prog.o bosatsu_ext_Bosatsu_l_Predef.o
+	gcc $(FLAGS) -o test_exe output.c bosatsu_runtime.o bosatsu_ext_Bosatsu_l_Prog.o bosatsu_ext_Bosatsu_l_Predef.o
 
 test_out: test_exe
 	./test_exe > output.log 2>&1 || { cat output.log; rm -f output.log; false; }