Simplify out_of_bounds checks

src/symbolic/symbolic_memory_concretizing.ml

@@ -108,16 +108,12 @@ module Backend = struct
  match Smtml.Expr.view a with
  | Val (Num (I32 _)) -> return (Ok a) (* An i32 is a valid address *)
  | Ptr { base; offset } -> (
- let (* A pointer is valid if it's within bounds. *)
- open Symbolic_value in
+ let open Symbolic_value in
+ (* A pointer is valid if it's within bounds. *)
  match Hashtbl.find m.chunks base with
  | exception Not_found -> return (Error Trap.Memory_leak_use_after_free)
  | size ->
- let base = const_i32 base in
- let ptr = I32.add base offset in
- let+ is_out_of_bounds =
- select (Bool.or_ (I32.lt ptr base) (I32.ge ptr (I32.add base size)))
- in
+ let+ is_out_of_bounds = select (I32.ge_u offset size) in
  if is_out_of_bounds then Error Trap.Memory_heap_buffer_overflow
  else Ok a )
  | _ ->