Dissect_letrec generates a Ltail

Author: chambart

middle_end/flambda2/from_lambda/dissect_letrec.ml

@@ -537,6 +537,9 @@ let rec prepare_letrec (recursive_set : Ident.Set.t)
   | Lregion (body, _) ->
     let letrec = prepare_letrec recursive_set current_let body letrec in
     { letrec with needs_region = true }
+  | Ltail _body ->
+    (* No tail expected here *)
+    assert false
   [@@ocaml.warning "-fragile-match"]
 
 let dissect_letrec ~bindings ~body =
@@ -573,18 +576,10 @@ let dissect_letrec ~bindings ~body =
         id, Lprim (Pccall desc, [size], Loc_unknown))
       letrec.blocks
   in
-  let real_body = body in
-  let bound_ids_freshening =
-    List.map (fun (bound_id, _) -> bound_id, Ident.rename bound_id) bindings
-    |> Ident.Map.of_list
-  in
-  let cont = next_raise_count () in
   let body =
     if not letrec.needs_region
     then body
-    else
-      let args = List.map (fun (bound_id, _) -> Lvar bound_id) bindings in
-      Lstaticraise (cont, args)
+    else Ltail body
   in
   let effects_then_body = lsequence (letrec.effects, body) in
   let functions =
@@ -616,18 +611,7 @@ let dissect_letrec ~bindings ~body =
       with_preallocations letrec.consts
   in
   let substituted = Lambda.rename letrec.substitution with_constants in
-  let body_layout = Lambda.layout_top in
-  if not letrec.needs_region
-  then substituted
-  else
-    Lstaticcatch
-      ( Lregion (Lambda.rename bound_ids_freshening substituted, body_layout),
-        ( cont,
-          List.map
-            (fun (bound_id, _) -> bound_id, Lambda.layout_letrec)
-            bindings ),
-        real_body,
-        body_layout )
+  substituted
 
 type dissected =
   | Dissected of Lambda.lambda