PVS-Studio warning V595 for FlightGear

bool FGAIShip::initFlightPlan() {
  ....
  prev = fp->getPreviousWaypoint();
  ....
  setHeading(getCourse(prev->getLatitude(),
                       prev->getLongitude(),
                       curr->getLatitude(),
                       curr->getLongitude()));
  ....
  if (prev)
    init = true;
  ....
}

This suspicious code was found in FlightGear project by PVS-Studio static code analyzer.
Warning message is:
V595 The 'prev' pointer was utilized before it was verified against nullptr. Check lines: 858, 868. aiship.cxx 858

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/