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

src/compiler/all-nodes.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #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++) {
     for (Node* const input : live[i]->inputs()) {
       if (input == nullptr) {
         // TODO(titzer): print a warning.
         continue;
       }
       if (input->id() >= graph->NodeCount()) {
         // 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