func mustParse(t *testing.T, dag string) *Graph {
	t.Helper()
	g, err := Parse(dag)
	if err != nil {
		t.Fatal(err)
	}
	return g
}

func wantEdges(t *testing.T, g *Graph, edges string) {
	t.Helper()

	wantEdges := strings.Fields(edges)
	wantEdgeMap := make(map[string]bool)
	for _, e := range wantEdges {
		wantEdgeMap[e] = true
	}

	for _, n1 := range g.Nodes {
		for _, n2 := range g.Nodes {

}

// edgeEntropyScore computes the entropy value for a set of edges
// coming in or out of a node. Entropy (as defined in information
// theory) refers to the amount of information encoded by the set of
// edges. A set of edges that have a more interesting distribution of
// samples gets a higher score.
func edgeEntropyScore(n *Node, edges EdgeMap, self int64) float64 {
	score := float64(0)
	total := self

        List<MetadataGraphEdge> edges = getIncidentEdges(vTo);
        if (edges == null || edges.isEmpty()) {
            return null;
        }

        List<MetadataGraphEdge> res = new ArrayList<>(edges.size());

        for (MetadataGraphEdge e : edges) {
            if (e.getSource().equals(vFrom)) {
                res.add(e);
            }

  // * replace edges to "Enter" nodes, and edges from "Exit" nodes with edges
  //   to/from the corresponding frame node. In essence, we collapse the loop
  //   into a single node for the purpose of cycle detection in the enclosing
  //   graph.
  // * the body of the loop should now be disconnected from the rest of the
  //   graph; we make it acyclic by breaking loop backedges (edges outgoing from
  //   "NextIteration" nodes.

// These blocks were inserted to remove critical edges.
func trim(f *Func) {
	n := 0
	for _, b := range f.Blocks {
		if !trimmableBlock(b) {
			f.Blocks[n] = b
			n++
			continue
		}

		bPos := b.Pos
		bIsStmt := bPos.IsStmt() == src.PosIsStmt

		// Splice b out of the graph. NOTE: `mergePhi` depends on the
		// order, in which the predecessors edges are merged here.
		p, i := b.Preds[0].b, b.Preds[0].i

		var b bytes.Buffer
		g.TransitiveReduction()
		// Add cyclic edges for visualization.
		for k := range cyclicRanks {
			g.AddEdge(k, k)
		}
		// Reverse the graph. It's much easier to read this as
		// a "<" partial order than a ">" partial order. This
		// ways, locks are acquired from the top going down
		// and time moves forward over the edges instead of
		// backward.
		g.Transpose()
		generateDot(&b, g)

            if (!s.ok()) {
              return;
            }
            node_map[n] = copy;
          }

          // Only handle input edges. Output edges will be added later as
          // its output nodes' input edges.
          for (auto e : n->in_edges()) {
            if (node_map.find(e->src()) == node_map.end()) {
              s = errors::Internal("Cannot find node image for ",

)

type backedgesState struct {
	b *Block
	i int
}

// backedges returns a slice of successor edges that are back
// edges.  For reducible loops, edge.b is the header.
func backedges(f *Func) []Edge {
	edges := []Edge{}
	mark := make([]markKind, f.NumBlocks())
	stack := []backedgesState{}

	mark[f.Entry.ID] = notExplored

		}
	}

	edges := EdgeMap{}

	// Add nodes and nodelets to DOT builder.
	for _, n := range g.Nodes {
		builder.addNode(n, nodeIDMap[n], maxFlat)
		hasNodelets[n] = builder.addNodelets(n, nodeIDMap[n])

		// Collect all edges. Use a fake node to support multiple incoming edges.
		for _, e := range n.Out {
			edges[&Node{}] = e
		}
	}

  static final String MULTIPLE_EDGES_CONNECTING =
      "Cannot call edgeConnecting() when parallel edges exist between %s and %s. Consider calling "
          + "edgesConnecting() instead.";
  static final String PARALLEL_EDGES_NOT_ALLOWED =
      "Nodes %s and %s are already connected by a different edge. To construct a graph "
          + "that allows parallel edges, call allowsParallelEdges(true) on the Builder.";
  static final String SELF_LOOPS_NOT_ALLOWED =