Restrict floating control to minimal control-connected component.

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"
 #include "src/compiler/schedule.h"
 #include "src/compiler/zone-pool.h"
 #include "src/zone-containers.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
+class ControlEquivalence;
 class SpecialRPONumberer;
 
 // Computes a schedule from a graph, placing nodes into basic blocks and
 // ordering the basic blocks in the special RPO order.
 class Scheduler {
  public:
   // The complete scheduling algorithm. Creates a new schedule and places all
   // nodes from the graph into it.
   static Schedule* ComputeSchedule(Zone* zone, Graph* graph);
 
@@ skipping 12 matching lines @@
   //
   // 1) GetPlacement(): kUnknown -> kCoupled|kSchedulable|kFixed
   // 2) UpdatePlacement(): kCoupled|kSchedulable -> kFixed|kScheduled
   enum Placement { kUnknown, kSchedulable, kFixed, kCoupled, kScheduled };
 
   // 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.
     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_;        // Whether the node is fixed, schedulable,
                                  // coupled to another node, or not yet known.
   };
 
   Zone* zone_;
   Graph* graph_;
   Schedule* schedule_;
   NodeVectorVector scheduled_nodes_;     // Per-block list of nodes in reverse.
   NodeVector schedule_root_nodes_;       // Fixed root nodes seed the worklist.
   ZoneQueue<Node*> schedule_queue_;      // Worklist of schedulable nodes.
   ZoneVector<SchedulerData> node_data_;  // Per-node data for all nodes.
   SpecialRPONumberer* special_rpo_;      // Special RPO numbering of blocks.
+  ControlEquivalence* equivalence_;      // Control dependence equivalence.
 
   Scheduler(Zone* zone, Graph* graph, Schedule* schedule);
 
   inline SchedulerData DefaultSchedulerData();
   inline SchedulerData* GetData(Node* node);
 
   Placement GetPlacement(Node* node);
   void UpdatePlacement(Node* node, Placement placement);
 
   inline bool IsCoupledControlEdge(Node* node, int index);
@@ skipping 28 matching lines @@
 
   void FuseFloatingControl(BasicBlock* block, Node* node);
   void MovePlannedNodes(BasicBlock* from, BasicBlock* to);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SCHEDULER_H_