let get_expr_val expr =
let cexpr = constFold true expr in
match cexpr.enode with
| Const c ->
let rec get_constant_expr_val e =
match e with
| CChr c -> get_constant_expr_val (charConstToInt c)
| CInt64 (d64,_,_) -> Some d64
| _ -> None
in get_constant_expr_val c
| _ -> None