Allocation folding integrated into the GVN phase.

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 215 matching lines @@
   void Advance() { current_++; }
 
  private:
   const ZoneList<HBasicBlock*>* predecessor_list_;
   int current_;
 };
 
 
 class HInstructionIterator BASE_EMBEDDED {
  public:
-  explicit HInstructionIterator(HBasicBlock* block) : instr_(block->first()) { }
+  explicit HInstructionIterator(HBasicBlock* block)
+      : instr_(block->first()), next_(NULL) {

[Michael Starzinger, 2013/07/08 14:02:43]

nit: Use a ternary operator, easier to read.

[Hannes Payer (out of office), 2013/07/09 08:26:15]

Done.

+    if (!Done()) {
+      next_ = instr_->next();
+    }
+  }
 
   bool Done() { return instr_ == NULL; }
   HInstruction* Current() { return instr_; }
-  void Advance() { instr_ = instr_->next(); }
+  void Advance() {
+    instr_ = next_;
+    if (!Done()) {

[Michael Starzinger, 2013/07/08 14:02:43]

nit: Use a ternary operator, easier to read.

[Hannes Payer (out of office), 2013/07/09 08:26:15]

Done.

+      next_ = instr_->next();
+    } else {
+      next_ = NULL;
+    }
+  }
 
  private:
   HInstruction* instr_;
+  HInstruction* next_;
 };
 
 
 class HLoopInformation: public ZoneObject {
  public:
   HLoopInformation(HBasicBlock* loop_header, Zone* zone)
       : back_edges_(4, zone),
         loop_header_(loop_header),
         blocks_(8, zone),
         stack_check_(NULL) {
@@ skipping 71 matching lines @@
   }
   HConstant* GetConstantUndefined() const { return undefined_constant_.get(); }
   HConstant* GetConstant0();
   HConstant* GetConstant1();
   HConstant* GetConstantMinus1();
   HConstant* GetConstantTrue();
   HConstant* GetConstantFalse();
   HConstant* GetConstantHole();
   HConstant* GetConstantNull();
   HConstant* GetInvalidContext();
+  HConstant* GetConstantFreeSpaceMap();
 
   bool IsStandardConstant(HConstant* constant);
 
   HBasicBlock* CreateBasicBlock();
   HArgumentsObject* GetArgumentsObject() const {
     return arguments_object_.get();
   }
 
   void SetArgumentsObject(HArgumentsObject* object) {
     arguments_object_.set(object);
@@ skipping 137 matching lines @@
   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_the_hole_;
   SetOncePointer<HConstant> constant_null_;
   SetOncePointer<HConstant> constant_invalid_context_;
   SetOncePointer<HArgumentsObject> arguments_object_;
+  SetOncePointer<HConstant> constant_free_space_map_;
 
   HOsrBuilder* osr_;
 
   CompilationInfo* info_;
   Zone* zone_;
 
   bool is_recursive_;
   bool use_optimistic_licm_;
   bool has_soft_deoptimize_;
   bool depends_on_empty_array_proto_elements_;
@@ skipping 1603 matching lines @@
   EmbeddedVector<char, 64> filename_;
   HeapStringAllocator string_allocator_;
   StringStream trace_;
   int indent_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_H_