Cannot generate .cil.o file but .o file after running cilly

I ran cilly successfully using the following command

../bin/cilly --save-temps --domakeCFG -D HAPPY_MOOD -I myincludes tut3.c -o tut3

and the corresponding result is

gcc -D_GNUCC -E -D HAPPY_MOOD -I myincludes -DCIL=1 tut3.c -o ./tut3.i
/home/kaidiwang/.opam/4.05.0/bin/cilly.native --out ./tut3.cil.c --domakeCFG ./tut3.i
gcc -D_GNUCC -E -D HAPPY_MOOD -I myincludes ./tut3.cil.c -o ./tut3.cil.i
gcc -D_GNUCC -c -D HAPPY_MOOD -I myincludes -o ./tut3.o ./tut3.cil.i
gcc -D_GNUCC -o tut3 -D HAPPY_MOOD -I myincludes ./tut3.o

I got the files:
tut3 tut3.c tut3.cil.c tut3.cil.i tut3.cmi tut3.cmo tut3.i tut3.ml tut3.o tututil.cmi tututil.cmo tututil.ml

But how can I see the generated CFG?

Thank you in advance!