(*
 * Vericert: Verified high-level synthesis.
 * Copyright (C) 2022 Yann Herklotz <yann@yannherklotz.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *)

Require Import compcert.common.AST.
Require Import compcert.common.Errors.
Require Import compcert.common.Globalenvs.
Require Import compcert.lib.Integers.
Require Import compcert.lib.Maps.

Require Import vericert.common.Vericertlib.
Require Import vericert.hls.Gible.
Require Import vericert.hls.GibleSeq.
Require Import vericert.hls.Predicate.
Require Import vericert.bourdoncle.Bourdoncle.

#[local] Open Scope positive.

Definition elim_cond_s (fresh: predicate) (i: instr) :=
  match i with
  | RBexit p (RBcond c args n1 n2) =>
      (Pos.succ fresh,
       RBsetpred p c args fresh
       :: RBexit (combine_pred (Some (Plit (true, fresh))) p) (RBgoto n1)
       :: RBexit (combine_pred (Some (Plit (false, fresh))) p) (RBgoto n2)
       :: nil)
  | _ => (fresh, i :: nil)
  end.

(* Fixpoint elim_cond (fresh: predicate) (b: SeqBB.t) := *)
(*   match b with *)
(*   | RBexit p (RBcond c args n1 n2) :: b' => *)
(*       let (fresh', b'') := elim_cond fresh b' in *)
(*       (Pos.succ fresh', *)
(*           RBsetpred p c args fresh' *)
(*        :: RBexit (combine_pred (Some (Plit (true, fresh'))) p) (RBgoto n1) *)
(*        :: RBexit (combine_pred (Some (Plit (false, fresh'))) p) (RBgoto n1) *)
(*        :: b'') *)
(*   | i :: b' => *)
(*       let (fresh, b'') := elim_cond fresh b' in *)
(*       (fresh, i :: b'') *)
(*   | nil => (fresh, nil) *)
(*   end. *)

Definition elim_cond_fold (state: predicate * PTree.t SeqBB.t) (n: node) (b: SeqBB.t) :=
  let (p, ptree) := state in
  let (p', b') := replace_section elim_cond_s p b in
  (p', PTree.set n b' ptree).

Definition transf_function (f: function) : function :=
  mkfunction f.(fn_sig) f.(fn_params) f.(fn_stacksize)
             (snd (PTree.fold elim_cond_fold f.(fn_code) (max_pred_function f + 1, PTree.empty _)))
             f.(fn_entrypoint).

Definition transf_fundef (fd: fundef) : fundef :=
  transf_fundef transf_function fd.

Definition transf_program (p: program) : program :=
  transform_program transf_fundef p.