Allocation folding integrated into the GVN phase.

src/hydrogen.h

Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index 6c1aba5db66d709231b996207965af7146b758e9..ef2ac73f32283c7e178bfd3da0a4ecb4d52c378a 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -233,14 +233,27 @@ class HPredecessorIterator BASE_EMBEDDED {
 
 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_;
 };
 
 
@@ -332,6 +345,7 @@ class HGraph: public ZoneObject {
   HConstant* GetConstantHole();
   HConstant* GetConstantNull();
   HConstant* GetInvalidContext();
+  HConstant* GetConstantFreeSpaceMap();
 
   bool IsStandardConstant(HConstant* constant);
 
@@ -489,6 +503,7 @@ class HGraph: public ZoneObject {
   SetOncePointer<HConstant> constant_null_;
   SetOncePointer<HConstant> constant_invalid_context_;
   SetOncePointer<HArgumentsObject> arguments_object_;
+  SetOncePointer<HConstant> constant_free_space_map_;
 
   HOsrBuilder* osr_;