Array bounds check elimination.

src/hydrogen.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 73 matching lines @@
   int argument_count() const { return argument_count_; }
   void set_argument_count(int count) { argument_count_ = count; }
   int first_instruction_index() const { return first_instruction_index_; }
   void set_first_instruction_index(int index) {
     first_instruction_index_ = index;
   }
   int last_instruction_index() const { return last_instruction_index_; }
   void set_last_instruction_index(int index) {
     last_instruction_index_ = index;
   }
+  bool is_osr_entry() { return is_osr_entry_; }
+  void set_osr_entry() { is_osr_entry_ = true; }
 
   void AttachLoopInformation();
   void DetachLoopInformation();
   bool IsLoopHeader() const { return loop_information() != NULL; }
   bool IsStartBlock() const { return block_id() == 0; }
   void PostProcessLoopHeader(IterationStatement* stmt);
 
   bool IsFinished() const { return end_ != NULL; }
   void AddPhi(HPhi* phi);
   void RemovePhi(HPhi* phi);
@@ skipping 82 matching lines @@
   // Outgoing parameter count at block exit, set during lithium translation.
   int argument_count_;
   // Instruction indices into the lithium code stream.
   int first_instruction_index_;
   int last_instruction_index_;
   ZoneList<int> deleted_phis_;
   HBasicBlock* parent_loop_header_;
   bool is_inline_return_target_;
   bool is_deoptimizing_;
   bool dominates_loop_successors_;
+  bool is_osr_entry_;
 };
 
 
 class HPredecessorIterator BASE_EMBEDDED {
  public:
   explicit HPredecessorIterator(HBasicBlock* block)
       : predecessor_list_(block->predecessors()), current_(0) { }
 
   bool Done() { return current_ >= predecessor_list_->length(); }
   HBasicBlock* Current() { return predecessor_list_->at(current_); }
@@ skipping 12 matching lines @@
         loop_header_(loop_header),
         blocks_(8, zone),
         stack_check_(NULL) {
     blocks_.Add(loop_header, zone);
   }
   virtual ~HLoopInformation() {}
 
   const ZoneList<HBasicBlock*>* back_edges() const { return &back_edges_; }
   const ZoneList<HBasicBlock*>* blocks() const { return &blocks_; }
   HBasicBlock* loop_header() const { return loop_header_; }
+  HBasicBlock* loop_pre_header() const {
+    return loop_header_->predecessors()->at(0);
+  }
   HBasicBlock* GetLastBackEdge() const;
   void RegisterBackEdge(HBasicBlock* block);
 
   HStackCheck* stack_check() const { return stack_check_; }
   void set_stack_check(HStackCheck* stack_check) {
     stack_check_ = stack_check;
   }
 
  private:
   void AddBlock(HBasicBlock* block);
 
   ZoneList<HBasicBlock*> back_edges_;
   HBasicBlock* loop_header_;
   ZoneList<HBasicBlock*> blocks_;
   HStackCheck* stack_check_;
 };
 
 class BoundsCheckTable;
+class BoundsCheckValueInfoTable;
+class BoundsCheckRemovalBlockContext;
 class HGraph: public ZoneObject {
  public:
   explicit HGraph(CompilationInfo* info);
 
   Isolate* isolate() { return isolate_; }
   Zone* zone() const { return zone_; }
   CompilationInfo* info() const { return info_; }
 
   const ZoneList<HBasicBlock*>* blocks() const { return &blocks_; }
   const ZoneList<HPhi*>* phi_list() const { return phi_list_; }
   HBasicBlock* entry_block() const { return entry_block_; }
   HEnvironment* start_environment() const { return start_environment_; }
 
   void InitializeInferredTypes();
   void InsertTypeConversions();
   void MergeRemovableSimulates();
   void InsertRepresentationChanges();
   void MarkDeoptimizeOnUndefined();
   void ComputeMinusZeroChecks();
   void ComputeSafeUint32Operations();
   bool ProcessArgumentsObject();
   void EliminateRedundantPhis();
   void EliminateUnreachablePhis();
   void Canonicalize();
   void OrderBlocks();
   void AssignDominators();
   void ReplaceCheckedValues();
   void EliminateRedundantBoundsChecks();
+  void EliminateOrDehoistBoundsChecks();
   void DehoistSimpleArrayIndexComputations();
   void DeadCodeElimination();
   void PropagateDeoptimizingMark();
   void EliminateUnusedInstructions();
 
   // Returns false if there are phi-uses of the arguments-object
   // which are not supported by the optimizing compiler.
   bool CheckArgumentsPhiUses();
 
   // Returns false if there are phi-uses of an uninitialized const
   // which are not supported by the optimizing compiler.
   bool CheckConstPhiUses();
 
   void CollectPhis();
 
   void set_undefined_constant(HConstant* constant) {
     undefined_constant_.set(constant);
   }
   HConstant* GetConstantUndefined() const { return undefined_constant_.get(); }
+  HConstant* GetConstant0();
   HConstant* GetConstant1();
   HConstant* GetConstantMinus1();
   HConstant* GetConstantTrue();
   HConstant* GetConstantFalse();
   HConstant* GetConstantHole();
 
   HBasicBlock* CreateBasicBlock();
   HArgumentsObject* GetArgumentsObject() const {
     return arguments_object_.get();
   }
@@ skipping 78 matching lines @@
   void PropagateMinusZeroChecks(HValue* value, BitVector* visited);
   void RecursivelyMarkPhiDeoptimizeOnUndefined(HPhi* phi);
   void InsertRepresentationChangeForUse(HValue* value,
                                         HValue* use_value,
                                         int use_index,
                                         Representation to);
   void InsertRepresentationChangesForValue(HValue* value);
   void InferTypes(ZoneList<HValue*>* worklist);
   void InitializeInferredTypes(int from_inclusive, int to_inclusive);
   void CheckForBackEdge(HBasicBlock* block, HBasicBlock* successor);
-  void EliminateRedundantBoundsChecks(HBasicBlock* bb, BoundsCheckTable* table);
+  void EliminateRedundantBoundsChecks(HBasicBlock* bb,
+                                      BoundsCheckTable* table);
+  void EliminateOrDehoistBoundsChecks(
+      HBasicBlock* bb,
+      BoundsCheckRemovalBlockContext* previous_context);
 
   Isolate* isolate_;
   int next_block_id_;
   HBasicBlock* entry_block_;
   HEnvironment* start_environment_;
   ZoneList<HBasicBlock*> blocks_;
   ZoneList<HValue*> values_;
   ZoneList<HPhi*>* phi_list_;
   ZoneList<HInstruction*>* uint32_instructions_;
   SetOncePointer<HConstant> undefined_constant_;
+  SetOncePointer<HConstant> constant_0_;
   SetOncePointer<HConstant> constant_1_;
   SetOncePointer<HConstant> constant_minus1_;
   SetOncePointer<HConstant> constant_true_;
   SetOncePointer<HConstant> constant_false_;
   SetOncePointer<HConstant> constant_hole_;
   SetOncePointer<HArgumentsObject> arguments_object_;
 
   SetOncePointer<HBasicBlock> osr_loop_entry_;
   SetOncePointer<ZoneList<HUnknownOSRValue*> > osr_values_;
 
@@ skipping 1115 matching lines @@
   const char* filename_;
   HeapStringAllocator string_allocator_;
   StringStream trace_;
   int indent_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_H_