inline bool frame::equal(frame other) const {
  bool ret =  sp() == other.sp()
              && unextended_sp() == other.unextended_sp()
              && fp() == other.fp()
              && pc() == other.pc();
  assert(!ret || ret && cb() == other.cb() && _deopt_state == other._deopt_state, "inconsistent construction");
  return ret;
}