[stubs] Remove the is_jsarray bit from the TransitionElementsKindStub.

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index 36242405b14c0fa5afd1174cb5a54b1d3aae7fc8..e688bedcad1fd20b21f904329f9ceaaea1a81884 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -1432,15 +1432,61 @@ Handle<Code> StoreFastElementStub::GenerateCode() {
 
 template <>
 HValue* CodeStubGraphBuilder<TransitionElementsKindStub>::BuildCodeStub() {
+  ElementsKind const from_kind = casted_stub()->from_kind();
+  ElementsKind const to_kind = casted_stub()->to_kind();
+  HValue* const object = GetParameter(0);
+  HValue* const map = GetParameter(1);
+
+  // The {object} is known to be a JSObject (otherwise it wouldn't have elements
+  // anyways).
+  object->set_type(HType::JSObject());
+
   info()->MarkAsSavesCallerDoubles();
 
-  BuildTransitionElementsKind(GetParameter(0),
-                              GetParameter(1),
-                              casted_stub()->from_kind(),
-                              casted_stub()->to_kind(),
-                              casted_stub()->is_js_array());
+  DCHECK_IMPLIES(IsFastHoleyElementsKind(from_kind),
+                 IsFastHoleyElementsKind(to_kind));
+
+  if (AllocationSite::GetMode(from_kind, to_kind) == TRACK_ALLOCATION_SITE) {
+    Add<HTrapAllocationMemento>(object);
+  }
+
+  if (!IsSimpleMapChangeTransition(from_kind, to_kind)) {
+    HInstruction* elements = AddLoadElements(object);
+
+    IfBuilder if_objecthaselements(this);
+    if_objecthaselements.IfNot<HCompareObjectEqAndBranch>(
+        elements, Add<HConstant>(isolate()->factory()->empty_fixed_array()));
+    if_objecthaselements.Then();
+    {
+      // Determine the elements capacity.
+      HInstruction* elements_length = AddLoadFixedArrayLength(elements);
+
+      // Determine the effective (array) length.
+      IfBuilder if_objectisarray(this);
+      if_objectisarray.If<HHasInstanceTypeAndBranch>(object, JS_ARRAY_TYPE);
+      if_objectisarray.Then();
+      {
+        // The {object} is a JSArray, load the special "length" property.
+        Push(Add<HLoadNamedField>(object, nullptr,
+                                  HObjectAccess::ForArrayLength(from_kind)));
+      }
+      if_objectisarray.Else();
+      {
+        // The {object} is some other JSObject.
+        Push(elements_length);
+      }
+      if_objectisarray.End();
+      HValue* length = Pop();
+
+      BuildGrowElementsCapacity(object, elements, from_kind, to_kind, length,
+                                elements_length);
+    }
+    if_objecthaselements.End();
+  }
+
+  Add<HStoreNamedField>(object, HObjectAccess::ForMap(), map);
 
-  return GetParameter(0);
+  return object;
 }