let find_sub_stmts st = match st.skind with
| If(_,bl1,bl2,_) | TryExcept (bl1, _, bl2, _)
| TryFinally (bl1, bl2, _) -> bl1.bstmts@bl2.bstmts
| Block bl | Loop (_,bl, _, _, _) | Switch (_, bl, _, _) -> bl.bstmts
| UnspecifiedSequence seq -> List.map (fun (x,_,_,_) -> x) seq
| Continue _|Break _|Goto (_, _)|Return (_, _)|Instr _ -> []