diff --git a/compiler/minils/transformations/schedule_interf.ml b/compiler/minils/transformations/schedule_interf.ml
index 582508f..ea7c3be 100644
--- a/compiler/minils/transformations/schedule_interf.ml
+++ b/compiler/minils/transformations/schedule_interf.ml
@@ -65,18 +65,20 @@ struct
       nb_def_vars - nb_killed_vars + b
 
     in
-    let eqs_wcost = List.map (fun eq -> (eq, cost eq)) rem_eqs in
-    let compare_eqs_wcost (_,c1) (_,c2) = compare c1 c2 in
-    let sorted_eqs_wcost = List.stable_sort compare_eqs_wcost eqs_wcost in
-    let rec min_same_ck sorted_eqs = match sorted_eqs with
-      | [] -> Misc.internal_error "no next equation to schedule"
-      | [(eq,_)] -> eq
-      | (eq1,c1)::(eq2,c2)::l ->
-        if (c2 > c1) || (Clocks.same_control (eq_clock eq1) ck)
-        then eq1 (* choosen since either the last with min cost or min and right clock *)
-        else min_same_ck ((eq2,c2)::l)
+    (* returns the minimum element of the list with same_ctrl = true. If there is no such element,
+       return the minimum of the list. *)
+    let rec min_same_ck (min_eq, min_c, min_same_ctrl) l = match l with
+      | [] -> min_eq
+      | (eq, c, same_ctrl)::l ->
+          if (c < min_c && (same_ctrl = min_same_ctrl)) or (same_ctrl && not min_same_ctrl) then
+            min_same_ck (eq, c, same_ctrl) l
+          else
+            min_same_ck (min_eq, min_c, min_same_ctrl) l
     in
-    min_same_ck sorted_eqs_wcost
+    let eqs_wcost =
+      List.map (fun eq -> (eq, cost eq, Clocks.same_control (eq_clock eq) ck)) rem_eqs in
+    let (eq, c, same_ctrl), eqs_wcost = Misc.assert_1min eqs_wcost in
+    min_same_ck (eq, c, same_ctrl) eqs_wcost
 end
 
 (** Returns the list of 'free' nodes in the dependency graph (nodes without
@@ -140,9 +142,6 @@ let node _ () f =
     f, ()
 
 let program p =
-  let mall = !Compiler_options.interf_all in
-  (* Compiler_options.interf_all := false; *)
   let funs = { Mls_mapfold.defaults with Mls_mapfold.node_dec = node } in
   let p, () = Mls_mapfold.program_it funs () p in
-  Compiler_options.interf_all := mall;
   p