Fix guarded_cid handling: add field to list of guarded_field at LoadField creation time.

runtime/vm/flow_graph_optimizer.cc

Index: runtime/vm/flow_graph_optimizer.cc
===================================================================
--- runtime/vm/flow_graph_optimizer.cc	(revision 20996)
+++ runtime/vm/flow_graph_optimizer.cc	(working copy)
@@ -21,9 +21,6 @@
 
 DEFINE_FLAG(bool, array_bounds_check_elimination, true,
     "Eliminate redundant bounds checks.");
-// TODO(srdjan): Enable/remove flag once it works.
-DEFINE_FLAG(bool, inline_getter_with_guarded_cid, false,
-    "Inline implict getter using guarded cid");
 DEFINE_FLAG(bool, load_cse, true, "Use redundant load elimination.");
 DEFINE_FLAG(int, max_polymorphic_checks, 4,
     "Maximum number of polymorphic check, otherwise it is megamorphic.");
@@ -1199,10 +1196,12 @@
       AbstractType::ZoneHandle(field.type()),
       field.is_final());
   if (field.guarded_cid() != kIllegalCid) {
+    Field* the_field = &Field::ZoneHandle(field.raw());
     if (!field.is_nullable() || (field.guarded_cid() == kNullCid)) {
       load->set_result_cid(field.guarded_cid());
+      guarded_fields_->Add(the_field);
     }
-    load->set_field(&Field::ZoneHandle(field.raw()));
+    load->set_field(the_field);
   }
   load->set_field_name(String::Handle(field.name()).ToCString());
 
@@ -1211,14 +1210,12 @@
   call->RemoveEnvironment();
   ReplaceCall(call, load);
 
-  if (FLAG_inline_getter_with_guarded_cid) {
-    if (load->result_cid() != kDynamicCid) {
-      // Reset value types if guarded_cid was used.
-      for (Value::Iterator it(load->input_use_list());
-           !it.Done();
-           it.Advance()) {
-        it.Current()->SetReachingType(NULL);
-      }
+  if (load->result_cid() != kDynamicCid) {
+    // Reset value types if guarded_cid was used.
+    for (Value::Iterator it(load->input_use_list());
+         !it.Done();
+         it.Advance()) {
+      it.Current()->SetReachingType(NULL);
     }
   }
 }