(*
 * Copyright (c) 2009-2013, Monoidics ltd.
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *)

(** The Smallfoot Intermediate Language: Binary Operators *)

open! IStd

(** Binary operations *)
type t =
  | PlusA of Typ.ikind option  (** arithmetic + *)
  | PlusPI  (** pointer + integer *)
  | MinusA of Typ.ikind option  (** arithmetic - *)
  | MinusPI  (** pointer - integer *)
  | MinusPP  (** pointer - pointer *)
  | Mult of Typ.ikind option  (** * *)
  | Div  (** / *)
  | Mod  (** % *)
  | Shiftlt  (** shift left *)
  | Shiftrt  (** shift right *)
  | Lt  (** < (arithmetic comparison) *)
  | Gt  (** > (arithmetic comparison) *)
  | Le  (** <= (arithmetic comparison) *)
  | Ge  (** >= (arithmetic comparison) *)
  | Eq  (** == (arithmetic comparison) *)
  | Ne  (** != (arithmetic comparison) *)
  | BAnd  (** bitwise and *)
  | BXor  (** exclusive-or *)
  | BOr  (** inclusive-or *)
  | LAnd  (** logical and. Does not always evaluate both operands. *)
  | LOr  (** logical or. Does not always evaluate both operands. *)
[@@deriving compare]

val str : Pp.env -> t -> string

val equal : t -> t -> bool

val injective : t -> bool
(** This function returns true if the operation is injective wrt. each argument: op(e,-) and op(-,
    e) is injective for all e. The return value false means "don't know". *)

val is_zero_runit : t -> bool
(** This function returns true if 0 is the right unit of [binop]. The return value false means
    "don't know". *)

val symmetric : t -> t option
(** [symmetric bop] returns' [Some bop'] if [x bop y] if and only if [y bop' x] for all x, y, or
    [None] if no such [bop'] exists *)

val negate : t -> t option
(** [negate bop] returns' [Some bop'] if [not (x bop y)] if and only if [x bop' y] for all x, y, or
    [None] if no such [bop'] exists *)