message: skip instruction iteration when no changes
  Summary: Makes things a little bit faster.
diff: @@ -18,6 +18,10 @@ void CFGMutation::clear() {
  }
  void CFGMutation::flush() {
  + if (m_changes.empty()) {
  + return;
  + }
  +
  auto ii = InstructionIterable(m_cfg);
  for (auto it = ii.begin(); !m_changes.empty() && !it.is_end();) {
  auto c = m_changes.find(it->insn);
  