[turbofan] Add support for advanced reducers.

src/compiler/node-marker.cc

 // Copyright 2015 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/node-marker.h"
 
 #include "src/compiler/graph.h"
 #include "src/compiler/node.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 NodeMarkerBase::NodeMarkerBase(Graph* graph, uint32_t num_states)
     : mark_min_(graph->mark_max_), mark_max_(graph->mark_max_ += num_states) {
-  DCHECK(num_states > 0);         // user error!
-  DCHECK(mark_max_ > mark_min_);  // check for wraparound.
+  DCHECK_NE(0u, num_states);        // user error!
+  DCHECK_LT(mark_min_, mark_max_);  // check for wraparound.
 }
 
 
 Mark NodeMarkerBase::Get(Node* node) {
   Mark mark = node->mark();
   if (mark < mark_min_) {
     mark = mark_min_;
     node->set_mark(mark_min_);
   }
   DCHECK_LT(mark, mark_max_);
   return mark - mark_min_;
 }
 
 
 void NodeMarkerBase::Set(Node* node, Mark mark) {
   DCHECK_LT(mark, mark_max_ - mark_min_);
   DCHECK_LT(node->mark(), mark_max_);
   node->set_mark(mark + mark_min_);
 }
 
+
+void NodeMarkerBase::Reset(Graph* graph) {
+  uint32_t const num_states = mark_max_ - mark_min_;
+  mark_min_ = graph->mark_max_;
+  mark_max_ = graph->mark_max_ += num_states;
+  DCHECK_LT(mark_min_, mark_max_);  // check for wraparound.
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8