diff --git a/compiler/minils/mls_utils.ml b/compiler/minils/mls_utils.ml
index dde7852..16f9623 100644
--- a/compiler/minils/mls_utils.ml
+++ b/compiler/minils/mls_utils.ml
@@ -36,7 +36,7 @@ let rec bounds_list ty =
 (** @return the [var_dec] object corresponding to the name [n]
     in a list of [var_dec]. *)
 let rec vd_find n = function
-  | [] -> Format.eprintf "Not found var %s@." (name n); raise Not_found
+  | [] -> (*Format.eprintf "Not found var %s@." (name n);*) raise Not_found
   | vd::l ->
       if vd.v_ident = n then vd else vd_find n l
 
diff --git a/compiler/minils/transformations/normalize_mem.ml b/compiler/minils/transformations/normalize_mem.ml
index bb83348..2a4d9cb 100644
--- a/compiler/minils/transformations/normalize_mem.ml
+++ b/compiler/minils/transformations/normalize_mem.ml
@@ -9,26 +9,30 @@ open Mls_mapfold
        o = mem_o
 *)
 
-let eq _ (v, eqs) eq = match eq.eq_lhs, eq.eq_rhs.e_desc with
+let rec vd_replace vd by_vd vd_l = match vd_l with
+  | [] -> []
+  | h::t -> if h.v_ident = vd.v_ident then by_vd::t else h::(vd_replace vd by_vd t)
+
+let eq _ (locals, eqs, outs) eq = match eq.eq_lhs, eq.eq_rhs.e_desc with
   | Evarpat x, Efby _ ->
-      if not (Mls_utils.vd_mem x v) then (* this memory is also an output *)
+      (try
+        let vd_out = Mls_utils.vd_find x outs in (* this memory is also an output *)
         let ty = eq.eq_rhs.e_ty in
-        let x_copy = Idents.gen_var "normalize_mem" ("mem_"^(Idents.name x)) in
-        let vd = mk_var_dec ~clock:eq.eq_rhs.e_ck x_copy ty in
-        let x_copy_exp = mk_exp ty (Eextvalue (mk_extvalue ~ty:ty (Wvar x_copy))) in
-        let eq_copy = { eq with eq_rhs = x_copy_exp } in
-        let eq = { eq with eq_lhs = Evarpat x_copy } in
-          eq, (vd::v, eq_copy::eq::eqs)
-      else
-        eq, (v, eq::eqs)
+        let x_copy = Idents.gen_var "normalize_mem" ("out_"^(Idents.name x)) in
+        let vd_x_copy = mk_var_dec ~clock:eq.eq_rhs.e_ck x_copy ty in
+        let exp_x = mk_exp ty (Eextvalue (mk_extvalue ~ty:ty (Wvar x))) in
+        let eq_copy = { eq with eq_lhs = Evarpat x_copy; eq_rhs = exp_x } in
+        eq, (vd_out::locals, eq::eq_copy::eqs, vd_replace vd_out vd_x_copy outs)
+      with Not_found -> (* this memory is not an output *)
+        eq, (locals, eq::eqs, outs))
   | _, _ ->
-      eq, (v, eq::eqs)
+      eq, (locals, eq::eqs, outs)
 
 let node funs acc nd =
-  let nd, (v, eqs) = Mls_mapfold.node_dec funs (nd.n_local, []) nd in
-    { nd with n_local = v; n_equs = List.rev eqs }, acc
+  let nd, (v, eqs, o) = Mls_mapfold.node_dec funs (nd.n_local, [], nd.n_output) nd in
+    { nd with n_local = v; n_equs = List.rev eqs; n_output = o }, acc
 
 let program p =
   let funs = { Mls_mapfold.defaults with eq = eq; node_dec = node } in
-  let p, _ = Mls_mapfold.program_it funs ([], []) p in
+  let p, _ = Mls_mapfold.program_it funs ([], [], []) p in
     p