private static LinkedHashSet<Integer> getFragmentInstructions(GrStatement first, GrStatement last, Instruction[] flow) {
    LinkedHashSet<Integer> result = new LinkedHashSet<>();
    for (Instruction instruction : flow) {
      if (isInFragment(instruction, first, last)) {
        result.add(instruction.num());
      }
    }
    return result;
  }
private static LinkedHashSet<Integer> getFragmentInstructions(GrStatement first, GrStatement last, Instruction[] flow)