Switch schedule early phase to basic blocks.

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 13 matching lines @@
   static Schedule* ComputeSchedule(Graph* graph);
 
   // Compute the RPO of blocks in an existing schedule.
   static BasicBlockVector* ComputeSpecialRPO(Schedule* schedule);
 
  private:
   enum Placement { kUnknown, kSchedulable, kFixed };
 
   // Per-node data tracked during scheduling.
   struct SchedulerData {
+    BasicBlock* minimum_block_;  // Minimum legal RPO placement.
     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,
                                  // or not yet known.
   };
 
   Zone* zone_;
   Graph* graph_;
   Schedule* schedule_;
@@ skipping 42 matching lines @@
 
   bool ConnectFloatingControl();
   void ConnectFloatingControlSubgraph(BasicBlock* block, Node* node);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SCHEDULER_H_