heptagon/compiler/obc/control.ml
Adrien Guatto 4794045208 Reworked Obc AST: from right patterns to extvalues.
I introduced a notion of extended values in Obc expressions,
replacing the Epattern constructor. Patterns may now only
occur at their rightful place, on the left of an assignment.

This change allows to index global constant arrays.
2011-05-30 16:25:00 +02:00

69 lines
2.1 KiB
OCaml

(**************************************************************************)
(* *)
(* Heptagon *)
(* *)
(* Author : Marc Pouzet *)
(* Organization : Demons, LRI, University of Paris-Sud, Orsay *)
(* *)
(**************************************************************************)
(* control optimisation *)
open Idents
open Misc
open Obc
open Obc_utils
open Clocks
open Obc_mapfold
let fuse_blocks b1 b2 =
{ b1 with b_locals = b1.b_locals @ b2.b_locals;
b_body = b1.b_body @ b2.b_body }
let rec find c = function
| [] -> raise Not_found
| (c1, s1) :: h ->
if c = c1 then s1, h else let s, h = find c h in s, (c1, s1) :: h
let is_deadcode = function
| Aassgn (lhs, e) ->
(match e.e_desc with
| Eextvalue w ->
let w' = ext_value_of_pattern lhs in
w = w' (* TODO: proper compare *)
| _ -> false
)
| Acase (_, []) -> true
| Afor(_, _, _, { b_body = [] }) -> true
| _ -> false
let rec joinlist l =
let l = List.filter (fun a -> not (is_deadcode a)) l in
match l with
| [] -> []
| [s1] -> [s1]
| s1::s2::l ->
match s1, s2 with
| Acase(e1, h1),
Acase(e2, h2) when e1.e_desc = e2.e_desc ->
joinlist ((Acase(e1, joinhandlers h1 h2))::l)
| s1, s2 -> s1::(joinlist (s2::l))
and join_block b =
{ b with b_body = joinlist b.b_body }
and joinhandlers h1 h2 =
match h1 with
| [] -> h2
| (c1, s1) :: h1' ->
let s1', h2' =
try let s2, h2'' = find c1 h2 in fuse_blocks s1 s2, h2''
with Not_found -> s1, h2 in
(c1, join_block s1') :: joinhandlers h1' h2'
let block funs acc b =
{ b with b_body = joinlist b.b_body }, acc
let program p =
let p, _ = program_it { defaults with block = block } () p in
p