During graph scheduling, traverse the roots in one go.

src/compiler/scheduler.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/scheduler.h"
 
 #include "src/compiler/graph.h"
 #include "src/compiler/graph-inl.h"
 #include "src/compiler/node.h"
 #include "src/compiler/node-properties.h"
@@ skipping 603 matching lines @@
 
 
 void Scheduler::ScheduleLate() {
   if (FLAG_trace_turbo_scheduler) {
     PrintF("------------------- SCHEDULE LATE -----------------\n");
   }
 
   // Schedule: Places nodes in dominator block of all their uses.
   ScheduleLateNodeVisitor schedule_late_visitor(this);
 
-  for (NodeVectorIter i = schedule_root_nodes_.begin();
-       i != schedule_root_nodes_.end(); ++i) {
-    // TODO(mstarzinger): Make the scheduler eat less memory.
+  {
     Zone zone(zone_->isolate());

[Michael Starzinger, 2014/08/14 13:27:54]

As experimented offline: We should now be able to get by without a temporary
zone here.

     GenericGraphVisit::Visit<ScheduleLateNodeVisitor,
                              NodeInputIterationTraits<Node> >(
-        graph_, &zone, *i, &schedule_late_visitor);
+        graph_, &zone, schedule_root_nodes_.begin(), schedule_root_nodes_.end(),
+        &schedule_late_visitor);
   }
 
   // Add collected nodes for basic blocks to their blocks in the right order.
   int block_num = 0;
   for (NodeVectorVectorIter i = scheduled_nodes_.begin();
        i != scheduled_nodes_.end(); ++i) {
     for (NodeVectorRIter j = i->rbegin(); j != i->rend(); ++j) {
       schedule_->AddNode(schedule_->all_blocks_.at(block_num), *j);
     }
     block_num++;
@@ skipping 401 matching lines @@
 
 #if DEBUG
   if (FLAG_trace_turbo_scheduler) PrintRPO(num_loops, loops, final_order);
   VerifySpecialRPO(num_loops, loops, final_order);
 #endif
   return final_order;
 }
 }
 }
 }  // namespace v8::internal::compiler