fexpr: Add %begin_region and %end_region, tests6.ml (ocaml-flambd…

…a#1172)

middle_end/flambda2/compare/compare.ml

@@ -660,6 +660,10 @@ let unary_prim_ops env (prim_op1 : Flambda_primitive.unary_primitive)
 
 let primitives env prim1 prim2 : Flambda_primitive.t Comparison.t =
   match (prim1 : Flambda_primitive.t), (prim2 : Flambda_primitive.t) with
+  | Nullary prim_op1, Nullary prim_op2 ->
+    if Flambda_primitive.equal_nullary_primitive prim_op1 prim_op2
+    then Equivalent
+    else Different { approximant = prim1 }
   | Unary (prim_op1, arg1), Unary (prim_op2, arg2) ->
     pairs ~f1:unary_prim_ops ~f2:simple_exprs ~subst2:subst_simple env
       (prim_op1, arg1) (prim_op2, arg2)

middle_end/flambda2/parser/fexpr.ml

@@ -241,9 +241,12 @@ type signed_or_unsigned = Flambda_primitive.signed_or_unsigned =
   | Signed
   | Unsigned
 
+type nullop = Begin_region
+
 type unop =
   | Array_length
   | Box_number of box_kind
+  | End_region
   | Get_tag
   | Is_flat_float_array
   | Is_int
@@ -312,6 +315,7 @@ type ternop = Array_set of array_kind * init_or_assign
 type varop = Make_block of tag_scannable * mutability
 
 type prim =
+  | Nullary of nullop
   | Unary of unop * simple
   | Binary of binop * simple * simple
   | Ternary of ternop * simple * simple * simple

middle_end/flambda2/parser/fexpr_to_flambda.ml

@@ -347,13 +347,17 @@ let or_variable f env (ov : _ Fexpr.or_variable) : _ Or_variable.t =
   | Const c -> Const (f c)
   | Var v -> Var (find_var env v, Debuginfo.none)
 
+let nullop (nullop : Fexpr.nullop) : Flambda_primitive.nullary_primitive =
+  match nullop with Begin_region -> Begin_region
+
 let unop env (unop : Fexpr.unop) : Flambda_primitive.unary_primitive =
   match unop with
   | Array_length -> Array_length
   | Box_number bk -> Box_number (bk, Alloc_mode.For_allocations.heap)
   | Unbox_number bk -> Unbox_number bk
   | Tag_immediate -> Tag_immediate
   | Untag_immediate -> Untag_immediate
+  | End_region -> End_region
   | Get_tag -> Get_tag
   | Is_flat_float_array -> Is_flat_float_array
   | Is_int -> Is_int { variant_only = true } (* CR vlaviron: discuss *)
@@ -436,6 +440,7 @@ let varop (varop : Fexpr.varop) n : Flambda_primitive.variadic_primitive =
 
 let prim env (p : Fexpr.prim) : Flambda_primitive.t =
   match p with
+  | Nullary op -> Nullary (nullop op)
   | Unary (op, arg) -> Unary (unop env op, simple env arg)
   | Binary (op, a1, a2) -> Binary (binop op, simple env a1, simple env a2)
   | Ternary (op, a1, a2, a3) ->
@@ -977,7 +982,8 @@ let bind_all_code_ids env (unit : Fexpr.flambda_unit) =
           env bindings
       in
       go env body
-    | Let _ | Let_cont _ | Apply _ | Apply_cont _ | Switch _ | Invalid _ -> env
+    | Let { body; _ } | Let_cont { body; _ } -> go env body
+    | Apply _ | Apply_cont _ | Switch _ | Invalid _ -> env
   in
   go env unit.body