Hi Hao Shen, > %4 = call float (i32)* (float (i32)*)* @get_ptr(float (i32)* @a1) > nounwind ;<float (i32)*> [#uses=1] > ~~~~~~~~~~~~~~~~~~~~ VERY STRANGE RETURN TYPE !!! this is a comment, and only exists to help the human reader. Comments start with a semi-colon (;). You can remove them if you like. Ciao, Duncan.