Fix field type handling in load elimination.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 44651cb942b7ac3063d018f04d71cf2cfe7f6806..837bbcd0a55d77c8b45b54053ba31326ef9aac2a 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -5052,15 +5052,15 @@ void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
     __ bind(deferred->check_maps());
   }
 
-  UniqueSet<Map> map_set = instr->hydrogen()->map_set();
+  const UniqueSet<Map>* map_set = instr->hydrogen()->map_set();
   Label success;
-  for (int i = 0; i < map_set.size() - 1; i++) {
-    Handle<Map> map = map_set.at(i).handle();
+  for (int i = 0; i < map_set->size() - 1; i++) {
+    Handle<Map> map = map_set->at(i).handle();
     __ CompareMap(reg, map);
     __ j(equal, &success, Label::kNear);
   }
 
-  Handle<Map> map = map_set.at(map_set.size() - 1).handle();
+  Handle<Map> map = map_set->at(map_set->size() - 1).handle();
   __ CompareMap(reg, map);
   if (instr->hydrogen()->has_migration_target()) {
     __ j(not_equal, deferred->entry());