message: Fix invalid derefence
  Summary: Do not dereference an iterator before checking whether it is the end of the container.
diff: @@ -670,8 +670,8 @@ void ControlFlowGraph::connect_blocks(BranchToTargets& branch_to_targets) {
  }
  auto next = std::next(it);
  - Block* next_b = next->second;
  if (fallthrough && next != m_blocks.end()) {
  + Block* next_b = next->second;
  TRACE(CFG, 6, "adding fallthrough goto %d -> %d", b->id(), next_b->id());
  add_edge(b, next_b, EDGE_GOTO);
  }
  