message: remove expr copy
diff: @@ -153,7 +153,7 @@ void Pointer::is_dereferenceable(unsigned bytes, unsigned align) {
  // general disjoint check for unsigned integer
  // This function assumes that both begin + len don't overflow
  -static expr disjoint(const expr begin1, const expr &len1, const expr begin2,
  +static expr disjoint(const expr &begin1, const expr &len1, const expr &begin2,
  const expr &len2) {
  return begin1.uge(begin2 + len2) || begin2.uge(begin1 + len1);
  }
  