Fix scheduler to correctly schedule nested diamonds.

src/compiler/scheduler.h

 // 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.
 
 #ifndef V8_COMPILER_SCHEDULER_H_
 #define V8_COMPILER_SCHEDULER_H_
 
 #include "src/v8.h"
 
 #include "src/compiler/opcodes.h"
@@ skipping 22 matching lines @@
  private:
   enum Placement { kUnknown, kSchedulable, kFixed };
 
   // Per-node data tracked during scheduling.
   struct SchedulerData {
     int unscheduled_count_;      // Number of unscheduled uses of this node.
     int minimum_rpo_;            // Minimum legal RPO placement.
     bool is_connected_control_;  // {true} if control-connected to the end node.
     bool is_floating_control_;   // {true} if control, but not control-connected
                                  // to the end node.
-    Placement placement_ : 3;    // Whether the node is fixed, schedulable,
+    Placement placement_;        // Whether the node is fixed, schedulable,
                                  // or not yet known.
+    NodeVector additional_dependencies;
   };
 
   Zone* zone_;
   Graph* graph_;
   Schedule* schedule_;
   NodeVectorVector scheduled_nodes_;
   NodeVector schedule_root_nodes_;
   ZoneVector<SchedulerData> node_data_;
   bool has_floating_control_;
 
   Scheduler(Zone* zone, Graph* graph, Schedule* schedule);
 
-  SchedulerData DefaultSchedulerData();
+  SchedulerData DefaultSchedulerData(Zone* zone);
 
   SchedulerData* GetData(Node* node) {
     DCHECK(node->id() < static_cast<int>(node_data_.size()));
     return &node_data_[node->id()];
   }
 
   void BuildCFG();
 
   Placement GetPlacement(Node* node);
 
@@ skipping 20 matching lines @@
 
   bool ConnectFloatingControl();
 
   void ConnectFloatingControlSubgraph(BasicBlock* block, Node* node);
 };
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_COMPILER_SCHEDULER_H_