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

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index d7ac7a8b149ffa07d343bf2f265ae94f0cc87c05..243372b1e3fbed335d72fddbc66102788f3ba869 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -2100,23 +2100,29 @@ LInstruction* LChunkBuilder::DoTransitionElementsKind(
     HTransitionElementsKind* instr) {
   ElementsKind from_kind = instr->original_map()->elements_kind();
   ElementsKind to_kind = instr->transitioned_map()->elements_kind();
-  if (IsSimpleMapChangeTransition(from_kind, to_kind)) {
-    LOperand* object = UseRegister(instr->object());
-    LOperand* new_map_reg = TempRegister();
-    LOperand* temp_reg = TempRegister();
-    LTransitionElementsKind* result =
-        new(zone()) LTransitionElementsKind(object, new_map_reg, temp_reg);
-    return DefineSameAsFirst(result);
-  } else {
-    LOperand* object = UseFixed(instr->object(), eax);
-    LOperand* fixed_object_reg = FixedTemp(edx);
-    LOperand* new_map_reg = FixedTemp(ebx);
-    LTransitionElementsKind* result =
-        new(zone()) LTransitionElementsKind(object,
-                                            new_map_reg,
-                                            fixed_object_reg);
-    return MarkAsCall(DefineFixed(result, eax), instr);
+  bool needs_pointer_map = !IsSimpleMapChangeTransition(from_kind, to_kind);
+
+  LOperand* object = UseRegister(instr->object());
+  LOperand* new_map_reg = TempRegister();
+  LOperand* temp_reg = TempRegister();
+  LTransitionElementsKind* result =
+      new(zone()) LTransitionElementsKind(object, new_map_reg, temp_reg);
+  if (needs_pointer_map) {
+    AssignPointerMap(result);
   }
+  return DefineSameAsFirst(result);
+
+  /*
+      // Old needs_pointer_map case
+      LOperand* object = UseFixed(instr->object(), eax);
+      LOperand* fixed_object_reg = FixedTemp(edx);
+      LOperand* new_map_reg = FixedTemp(ebx);
+      LTransitionElementsKind* result =
+          new(zone()) LTransitionElementsKind(object,
+                                              new_map_reg,
+                                              fixed_object_reg);
+      return MarkAsCall(DefineFixed(result, eax), instr);
+  */
 }