CristalCaveGem » LustreC

(* checks whether a variable is aliasable,

   depending on its (address) type *)

let is_aliasable var =

(* checks whether a variable [v] is an input of the [var] equation, with an address type.

   if so, [var] could not safely reuse/alias [v], should [v] be dead in the caller node,

    | None           -> []

    | Some (_, args) -> List.fold_right (fun e r -> match e.expr_desc with Expr_ident id -> id::r | _ -> r) args [] in

  fun v -> is_aliasable v && List.mem v.var_id inputs_var

(* replace variable [v] by [v'] in graph [g].

   [v'] is a dead variable

*)

    let disjoint_live = Disjunction.CISet.inter disjoint live in

    Log.report ~level:7 (fun fmt -> Format.fprintf fmt "disjoint live:%a@." Disjunction.pp_ciset disjoint_live);

    let reuse = Disjunction.CISet.max_elt disjoint_live in

    begin

      IdentDepGraph.add_edge ctx.dep_graph var.var_id reuse.var_id;

      Hashtbl.add ctx.policy var.var_id reuse;

      ctx.evaluated <- Disjunction.CISet.add var ctx.evaluated;

      (*Format.eprintf "%s reused by live@." var.var_id;*)

    let dead = Disjunction.CISet.filter (fun v -> is_graph_root v.var_id ctx.dep_graph) quasi_dead in

    Log.report ~level:7 (fun fmt -> Format.fprintf fmt "dead:%a@." Disjunction.pp_ciset dead);

    let reuse = Disjunction.CISet.choose dead in

    begin

      IdentDepGraph.add_edge ctx.dep_graph var.var_id reuse.var_id;

      Hashtbl.add ctx.policy var.var_id reuse;

      ctx.evaluated <- Disjunction.CISet.add var ctx.evaluated;

    end

      with Not_found ->

    begin