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-rw-r--r--sched/simplify.ml78
-rw-r--r--tests/Makefile1
2 files changed, 49 insertions, 30 deletions
diff --git a/sched/simplify.ml b/sched/simplify.ml
index 5ca4b99..4f2359e 100644
--- a/sched/simplify.ml
+++ b/sched/simplify.ml
@@ -20,6 +20,7 @@ module Smap = Map.Make(String)
(* Simplify cascade slicing/selecting *)
let cascade_slices p =
+ let usefull = ref false in
let slices = Hashtbl.create 42 in
let eqs_new = List.map
(fun (n, eq) -> (n, match eq with
@@ -31,10 +32,12 @@ let cascade_slices p =
(0, x)
in
Hashtbl.add slices n (u + dec, nx);
+ if nx <> x || dec <> 0 then usefull := true;
Eslice(u + dec, v + dec, Avar(nx))
| Eselect(u, Avar(x)) ->
begin try
let ku, kx = Hashtbl.find slices x in
+ usefull := true;
Eselect(ku + u, Avar(kx))
with
Not_found -> Eselect(u, Avar(x))
@@ -46,7 +49,7 @@ let cascade_slices p =
p_inputs = p.p_inputs;
p_outputs = p.p_outputs;
p_vars = p.p_vars;
- }, false
+ }, !usefull
(* Simplifies some trivial arithmetic possibilites :
a and 1 = a
@@ -60,24 +63,26 @@ let cascade_slices p =
select i const = const.[i]
*)
let arith_simplify p =
+ let usefull = ref false in
{
p_eqs = List.map
- (fun (n, eq) -> match eq with
- | Ebinop(Or, Aconst(VBit(false)), x) -> (n, Earg(x))
- | Ebinop(Or, Aconst(VBit(true)), x) -> (n, Earg(Aconst(VBit(true))))
- | Ebinop(Or, x, Aconst(VBit(false))) -> (n, Earg(x))
- | Ebinop(Or, x, Aconst(VBit(true))) -> (n, Earg(Aconst(VBit(true))))
+ (fun (n, eq) ->
+ let useless = ref false in
+ let neq = match eq with
+ | Ebinop(Or, Aconst(VBit(false)), x) -> Earg(x)
+ | Ebinop(Or, Aconst(VBit(true)), x) -> Earg(Aconst(VBit(true)))
+ | Ebinop(Or, x, Aconst(VBit(false))) -> Earg(x)
+ | Ebinop(Or, x, Aconst(VBit(true))) -> Earg(Aconst(VBit(true)))
- | Ebinop(And, Aconst(VBit(false)), x) -> (n, Earg(Aconst(VBit(false))))
- | Ebinop(And, Aconst(VBit(true)), x) -> (n, Earg(x))
- | Ebinop(And, x, Aconst(VBit(false))) -> (n, Earg(Aconst(VBit(false))))
- | Ebinop(And, x, Aconst(VBit(true))) -> (n, Earg(x))
+ | Ebinop(And, Aconst(VBit(false)), x) -> Earg(Aconst(VBit(false)))
+ | Ebinop(And, Aconst(VBit(true)), x) -> Earg(x)
+ | Ebinop(And, x, Aconst(VBit(false))) -> Earg(Aconst(VBit(false)))
+ | Ebinop(And, x, Aconst(VBit(true))) -> Earg(x)
- | Ebinop(Xor, Aconst(VBit(false)), x) -> (n, Earg(x))
- | Ebinop(Xor, x, Aconst(VBit(false))) -> (n, Earg(x))
+ | Ebinop(Xor, Aconst(VBit(false)), x) -> Earg(x)
+ | Ebinop(Xor, x, Aconst(VBit(false))) -> Earg(x)
- | Eslice(i, j, k) when i = j ->
- (n, Eselect(i, k))
+ | Eslice(i, j, k) when i = j -> Eselect(i, k)
| Econcat(Aconst(a), Aconst(b)) ->
let aa = match a with
@@ -88,43 +93,48 @@ let arith_simplify p =
| VBit(a) -> [| a |]
| VBitArray(a) -> a
in
- (n, Earg(Aconst(VBitArray(Array.append aa ba))))
+ Earg(Aconst(VBitArray(Array.append aa ba)))
| Eslice(i, j, Aconst(VBitArray(a))) ->
- (n, Earg(Aconst(VBitArray(Array.sub a i (j - i + 1)))))
+ Earg(Aconst(VBitArray(Array.sub a i (j - i + 1))))
| Eselect(i, Aconst(VBitArray(a))) ->
- (n, Earg(Aconst(VBit(a.(i)))))
+ Earg(Aconst(VBit(a.(i))))
- | _ -> (n, eq))
+ | _ -> useless := true; eq in
+ if not !useless then usefull := true;
+ (n, neq))
p.p_eqs;
p_inputs = p.p_inputs;
p_outputs = p.p_outputs;
p_vars = p.p_vars;
- }, false
+ }, !usefull
(* if x is one bit, then :
select 0 x = x
*)
let select_to_id p =
+ let usefull = ref false in
{
p_eqs = List.map
(fun (n, eq) -> match eq with
| Eselect(0, Avar(id)) when
Env.find id p.p_vars = TBit || Env.find id p.p_vars = TBitArray(1) ->
+ usefull := true;
(n, Earg(Avar(id)))
| _ -> (n, eq))
p.p_eqs;
p_inputs = p.p_inputs;
p_outputs = p.p_outputs;
p_vars = p.p_vars;
- }, false
+ }, !usefull
(*
If a = eqn(v1, v2, ...) and b = eqn(v1, v2, ...) <- the same equation
then say b = a
*)
let same_eq_simplify p =
+ let usefull = ref false in
let id_outputs =
(List.fold_left (fun x k -> Sset.add k x) Sset.empty p.p_outputs) in
let eq_map = Hashtbl.create 42 in
@@ -135,9 +145,10 @@ let same_eq_simplify p =
let simplify_eq (n, eq) =
if Sset.mem n id_outputs then
(n, eq)
- else if Hashtbl.mem eq_map eq then
+ else if Hashtbl.mem eq_map eq then begin
+ usefull := true;
(n, Earg(Avar(Hashtbl.find eq_map eq)))
- else begin
+ end else begin
Hashtbl.add eq_map eq n;
(n, eq)
end
@@ -148,7 +159,7 @@ let same_eq_simplify p =
p_inputs = p.p_inputs;
p_outputs = p.p_outputs;
p_vars = p.p_vars;
- }, false
+ }, !usefull
(* Replace one specific variable by another argument in the arguments of all equations
@@ -212,25 +223,32 @@ let rec eliminate_id p =
| None -> p, false
| Some(n, rep) -> fst (eliminate_id (eliminate_var n rep p)), true
+(* Eliminate dead variables *)
+let eliminate_dead p =
+ (p, false)
+
(* Topological sort *)
let topo_sort p =
(Scheduler.schedule p, false)
+
(* Apply all the simplification passes,
in the order given in the header of this file
*)
let rec simplify p =
let steps = [
- cascade_slices;
- arith_simplify;
- select_to_id;
- same_eq_simplify;
- eliminate_id;
- topo_sort;
+ topo_sort, "topo_sort";
+ cascade_slices, "cascade_slices";
+ arith_simplify, "arith_simplify";
+ select_to_id, "select_to_id";
+ same_eq_simplify, "same_eq_simplify";
+ eliminate_id, "eliminate_id";
] in
let pp, use = List.fold_left
- (fun (x, u) f ->
+ (fun (x, u) (f, n) ->
+ print_string n;
let xx, uu = f x in
+ print_string (if uu then "*\n" else "\n");
(xx, u || uu))
(p, false) steps in
if use then simplify pp else pp
diff --git a/tests/Makefile b/tests/Makefile
index 7f1e355..718cd70 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -15,4 +15,5 @@ SIM=../csim/csim
clean:
rm *.net
+ rm *.snet
rm *.dumb
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-21 17:31:19 +0000