let copy_var =
let counter = ref (-1) in
fun () ->
decr counter;
fun vi ->
let vi' = Cil_const.copy_with_new_vid vi in
vi'.vname <- vi.vname ^ "_unroll_" ^ (string_of_int (- !counter));
(match vi'.vlogic_var_assoc with
None -> ();
| Some lv -> lv.lv_name <- vi'.vname);
vi'