Remove filler map when folding allocations and turn on allocation folding.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index bdb2352edb8cc6080d8b3f2bfcba5a9b6407f96b..8e5b9bc41dc08c26f63a9241d07f99a6e7834586 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -3216,37 +3216,6 @@ void HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
   new_dominator_size->InsertBefore(dominator_allocate_instr);
   dominator_allocate_instr->UpdateSize(new_dominator_size);
 
-  // TODO(hpayer): Remove filler map but make sure new space is valid.
-  HInstruction* free_space_instr =
-      new(zone) HInnerAllocatedObject(dominator_allocate_instr,
-                                      dominator_size_constant,
-                                      type());
-  free_space_instr->InsertAfter(dominator_allocate_instr);
-  HConstant* filler_map = new(zone) HConstant(
-      isolate()->factory()->free_space_map(),
-      UniqueValueId(isolate()->heap()->free_space_map()),
-      Representation::Tagged(),
-      HType::Tagged(),
-      false,
-      true,
-      false,
-      false);
-  filler_map->InsertAfter(free_space_instr);
-
-  HInstruction* store_map = new(zone) HStoreNamedField(
-      free_space_instr, HObjectAccess::ForMap(), filler_map);
-  store_map->SetFlag(HValue::kHasNoObservableSideEffects);
-  store_map->InsertAfter(filler_map);
-
-  HInstruction* free_space_size = new(zone) HConstant(current_size_constant);
-  free_space_size->InsertAfter(store_map);
-  HObjectAccess access =
-      HObjectAccess::ForJSObjectOffset(FreeSpace::kSizeOffset);
-  HInstruction* store_size = new(zone) HStoreNamedField(
-      free_space_instr, access, free_space_size);
-  store_size->SetFlag(HValue::kHasNoObservableSideEffects);
-  store_size->InsertAfter(free_space_size);
-
   // After that replace the dominated allocate instruction.
   HInstruction* dominated_allocate_instr =
       new(zone) HInnerAllocatedObject(dominator_allocate_instr,