let change_mode res =
Wp_parameters.debug ~level:3
"[calculus] change to compute mode (clear wp table)@.";
begin try
let e_start = Cil2cfg.start_edge res.cfg in
let start_goal = find res e_start in
memo_goal_pass2 res start_goal [e_start]
with Not_found -> ()
end;
res.mode <- Pass2; HE.clear res.tbl