[turbofan] Don't compute unneeded gray set in AllNodes.

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/940403002

Cr-Commit-Position: refs/heads/master@{#26773}

src/compiler/all-nodes.cc

@@ -4,16 +4,16 @@
 
 #include "src/compiler/all-nodes.h"
 
+#include "src/compiler/graph.h"
+
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 AllNodes::AllNodes(Zone* local_zone, const Graph* graph)
-    : live(local_zone),
-      gray(local_zone),
-      state(graph->NodeCount(), AllNodes::kDead, local_zone) {
+    : live(local_zone), is_live(graph->NodeCount(), false, local_zone) {
   Node* end = graph->end();
-  state[end->id()] = AllNodes::kLive;
+  is_live[end->id()] = true;
   live.push_back(end);
   // Find all live nodes reachable from end.
   for (size_t i = 0; i < live.size(); i++) {
@@ -26,23 +26,14 @@ AllNodes::AllNodes(Zone* local_zone, const Graph* graph)
         // TODO(titzer): print a warning.
         continue;
       }
-      if (state[input->id()] != AllNodes::kLive) {
+      if (!is_live[input->id()]) {
+        is_live[input->id()] = true;
         live.push_back(input);
-        state[input->id()] = AllNodes::kLive;
       }
     }
   }
-
-  // Find all nodes that are not reachable from end that use live nodes.
-  for (size_t i = 0; i < live.size(); i++) {
-    for (Node* const use : live[i]->uses()) {
-      if (state[use->id()] == AllNodes::kDead) {
-        gray.push_back(use);
-        state[use->id()] = AllNodes::kGray;
-      }
-    }
-  }
-}
 }
-}
-}  // namespace v8::internal::compiler
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8

src/compiler/all-nodes.h

@@ -5,7 +5,6 @@
 #ifndef V8_COMPILER_ALL_NODES_H_
 #define V8_COMPILER_ALL_NODES_H_
 
-#include "src/compiler/graph.h"
 #include "src/compiler/node.h"
 #include "src/zone-containers.h"
 
@@ -17,25 +16,23 @@ namespace compiler {
 // from end.
 class AllNodes {
  public:
-  // Constructor. Traverses the graph and builds the {live} and {gray} sets.
+  // Constructor. Traverses the graph and builds the {live} sets.
   AllNodes(Zone* local_zone, const Graph* graph);
 
   bool IsLive(Node* node) {
-    return node != nullptr && node->id() < static_cast<int>(state.size()) &&
-           state[node->id()] == kLive;
+    if (!node) return false;
+    size_t id = node->id();
+    return id < is_live.size() && is_live[id];
   }
 
   NodeVector live;  // Nodes reachable from end.
-  NodeVector gray;  // Nodes themselves not reachable from end, but that
-                    // appear in use lists of live nodes.
 
  private:
-  enum State { kDead, kGray, kLive };
-
-  ZoneVector<State> state;
+  BoolVector is_live;
 };
-}
-}
-}  // namespace v8::internal::compiler
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_COMPILER_ALL_NODES_H_

src/compiler/graph-visualizer.cc

@@ -361,9 +361,17 @@ void GraphVisualizer::Print() {
       << "  concentrate=\"true\"\n"
       << "  \n";
 
+  // Find all nodes that are not reachable from end that use live nodes.
+  std::set<Node*> gray;
+  for (Node* const node : all_.live) {
+    for (Node* const use : node->uses()) {
+      if (!all_.IsLive(use)) gray.insert(use);
+    }
+  }
+
   // Make sure all nodes have been output before writing out the edges.
   for (Node* const node : all_.live) PrintNode(node, false);
-  for (Node* const node : all_.gray) PrintNode(node, true);
+  for (Node* const node : gray) PrintNode(node, true);
 
   // With all the nodes written, add the edges.
   for (Node* const node : all_.live) {

src/compiler/node.h

@@ -249,6 +249,7 @@ std::ostream& operator<<(std::ostream& os, const Node& n);
 
 // Typedefs to shorten commonly used Node containers.
 typedef ZoneDeque<Node*> NodeDeque;
+typedef ZoneSet<Node*> NodeSet;
 typedef ZoneVector<Node*> NodeVector;
 typedef ZoneVector<NodeVector> NodeVectorVector;
 

test/cctest/compiler/test-osr.cc

@@ -122,7 +122,12 @@ class OsrDeconstructorTester : public HandleAndZoneScope {
     CHECK(!nodes.IsLive(osr_normal_entry));
     CHECK(!nodes.IsLive(osr_loop_entry));
     // No dangling nodes should be left over.
-    CHECK_EQ(0u, nodes.gray.size());
+    for (Node* const node : nodes.live) {
+      for (Node* const use : node->uses()) {
+        CHECK(std::find(nodes.live.begin(), nodes.live.end(), use) !=
+              nodes.live.end());
+      }
+    }
   }
 };