A change in the way we place TransitionElementKinds in the tree.

src/hydrogen.h

Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index 98b05d147a290d67e10cbe57daae8bc2f73b02ea..1afb71fb5813f2957e0e9801db4e03ceca549276 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -91,6 +91,8 @@ class HBasicBlock: public ZoneObject {
   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();
@@ -193,6 +195,7 @@ class HBasicBlock: public ZoneObject {
   bool is_inline_return_target_;
   bool is_deoptimizing_;
   bool dominates_loop_successors_;
+  bool is_osr_entry_;
 };
 
 
@@ -242,6 +245,7 @@ class HLoopInformation: public ZoneObject {
   HStackCheck* stack_check_;
 };
 
+
 class BoundsCheckTable;
 class HGraph: public ZoneObject {
  public:
@@ -370,6 +374,18 @@ class HGraph: public ZoneObject {
     uint32_instructions_->Add(instr, zone());
   }
 
+  HArrayInstruction* RecordArrayInstruction(HArrayInstruction* instr) {
+    if (array_instructions_ == NULL) {
+      array_instructions_ = new(zone()) ZoneList<HArrayInstruction*>(4, zone());
+    }
+    array_instructions_->Add(instr, zone());
+    return instr;
+  }
+
+  ZoneList<HArrayInstruction*>* array_instructions() {
+    return array_instructions_;
+  }
+
  private:
   HConstant* GetConstant(SetOncePointer<HConstant>* pointer,
                          Handle<Object> value);
@@ -377,6 +393,7 @@ class HGraph: public ZoneObject {
                               int32_t integer_value);
 
   void MarkAsDeoptimizingRecursively(HBasicBlock* block);
+  void InsertElementsTransitions();
   void InsertTypeConversions(HInstruction* instr);
   void PropagateMinusZeroChecks(HValue* value, BitVector* visited);
   void RecursivelyMarkPhiDeoptimizeOnUndefined(HPhi* phi);
@@ -398,6 +415,7 @@ class HGraph: public ZoneObject {
   ZoneList<HValue*> values_;
   ZoneList<HPhi*>* phi_list_;
   ZoneList<HInstruction*>* uint32_instructions_;
+  ZoneList<HArrayInstruction*>* array_instructions_;
   SetOncePointer<HConstant> undefined_constant_;
   SetOncePointer<HConstant> constant_1_;
   SetOncePointer<HConstant> constant_minus1_;
@@ -1139,31 +1157,31 @@ class HGraphBuilder: public AstVisitor {
                                      HValue* right);
   HInstruction* BuildIncrement(bool returns_original_input,
                                CountOperation* expr);
-  HInstruction* BuildFastElementAccess(HValue* elements,
-                                       HValue* checked_key,
-                                       HValue* val,
-                                       HValue* dependency,
-                                       ElementsKind elements_kind,
-                                       bool is_store);
-
-  HInstruction* TryBuildConsolidatedElementLoad(HValue* object,
-                                                HValue* key,
-                                                HValue* val,
-                                                SmallMapList* maps);
-
-  HInstruction* BuildUncheckedMonomorphicElementAccess(HValue* object,
-                                                       HValue* key,
-                                                       HValue* val,
-                                                       HCheckMaps* mapcheck,
-                                                       Handle<Map> map,
-                                                       bool is_store);
-
-  HInstruction* BuildMonomorphicElementAccess(HValue* object,
-                                              HValue* key,
-                                              HValue* val,
-                                              HValue* dependency,
-                                              Handle<Map> map,
-                                              bool is_store);
+  HArrayInstruction* BuildFastElementAccess(HValue* elements,
+                                                    HValue* checked_key,
+                                                    HValue* val,
+                                                    HValue* dependency,
+                                                    ElementsKind elements_kind,
+                                                    bool is_store);
+
+  HArrayInstruction* TryBuildConsolidatedElementLoad(HValue* object,
+                                                           HValue* key,
+                                                           HValue* val,
+                                                           SmallMapList* maps);
+
+  HArrayInstruction* BuildUncheckedMonomorphicElementAccess(HValue* object,
+                                                   HValue* key,
+                                                   HValue* val,
+                                                   HCheckMaps* mapcheck,
+                                                   Handle<Map> map,
+                                                   bool is_store);
+
+  HArrayInstruction* BuildMonomorphicElementAccess(HValue* object,
+                                            HValue* key,
+                                            HValue* val,
+                                            HValue* dependency,
+                                            Handle<Map> map,
+                                            bool is_store);
 
   HValue* HandlePolymorphicElementAccess(HValue* object,
                                          HValue* key,
@@ -1198,7 +1216,7 @@ class HGraphBuilder: public AstVisitor {
                                           Property* expr,
                                           Handle<Map> map);
   HInstruction* BuildLoadKeyedGeneric(HValue* object, HValue* key);
-  HInstruction* BuildExternalArrayElementAccess(
+  HArrayInstruction* BuildExternalArrayElementAccess(
       HValue* external_elements,
       HValue* checked_key,
       HValue* val,