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

src/compiler/graph-visualizer.cc

 // Copyright 2013 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/graph-visualizer.h"
 
 #include <sstream>
 #include <string>
 
 #include "src/code-stubs.h"
@@ skipping 343 matching lines @@
 void GraphVisualizer::Print() {
   os_ << "digraph D {\n"
       << "  node [fontsize=8,height=0.25]\n"
       << "  rankdir=\"BT\"\n"
       << "  ranksep=\"1.2 equally\"\n"
       << "  overlap=\"false\"\n"
       << "  splines=\"true\"\n"
       << "  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) {
     for (Edge edge : node->use_edges()) {
       PrintEdge(edge);
     }
   }
   os_ << "}\n";
 }
 
@@ skipping 430 matching lines @@
         os << "#" << SafeId(i) << ":" << SafeMnemonic(i);
       }
       os << ")" << std::endl;
     }
   }
   return os;
 }
 }
 }
 }  // namespace v8::internal::compiler