Revert parts of r45502 and always generate guard field instructions.

runtime/vm/flow_graph_builder.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/class_finalizer.h"
@@ skipping 3486 matching lines @@
     const AbstractType& type =
         AbstractType::ZoneHandle(Z, node->field().type());
     const String& dst_name = String::ZoneHandle(Z, node->field().name());
     store_value = BuildAssignableValue(node->value()->token_pos(),
                                        store_value,
                                        type,
                                        dst_name);
   }
 
   if (FLAG_use_field_guards) {
-    if (node->field().guarded_cid() != kDynamicCid) {
-      store_value = Bind(BuildStoreExprTemp(store_value));
-      GuardFieldClassInstr* guard_field_class =
-          new(Z) GuardFieldClassInstr(store_value,
-                                   node->field(),
-                                   isolate()->GetNextDeoptId());
-      AddInstruction(guard_field_class);
-      store_value = Bind(BuildLoadExprTemp());
-      if (node->field().guarded_list_length() != Field::kNoFixedLength) {
-        GuardFieldLengthInstr* guard_field_length =
-            new(Z) GuardFieldLengthInstr(store_value,
-                                         node->field(),
-                                         isolate()->GetNextDeoptId());
-        AddInstruction(guard_field_length);
-        store_value = Bind(BuildLoadExprTemp());
-      } else {
-        // Advance deopt-id counter to remain in sync.
-        isolate()->GetNextDeoptId();
-      }
-    } else {
-      // Advance deopt-id counter to remain in sync.
-      isolate()->GetNextDeoptId();
-      isolate()->GetNextDeoptId();
-    }
+    store_value = Bind(BuildStoreExprTemp(store_value));
+    GuardFieldClassInstr* guard_field_class =
+        new(Z) GuardFieldClassInstr(store_value,
+                                 node->field(),
+                                 isolate()->GetNextDeoptId());
+    AddInstruction(guard_field_class);
+    store_value = Bind(BuildLoadExprTemp());
+    GuardFieldLengthInstr* guard_field_length =
+        new(Z) GuardFieldLengthInstr(store_value,
+                                     node->field(),
+                                     isolate()->GetNextDeoptId());
+    AddInstruction(guard_field_length);
+    store_value = Bind(BuildLoadExprTemp());
   }
   StoreInstanceFieldInstr* store =
       new(Z) StoreInstanceFieldInstr(node->field(),
                                      for_instance.value(),
                                      store_value,
                                      kEmitStoreBarrier,
                                      node->token_pos());
   // Maybe initializing unboxed store.
   store->set_is_potential_unboxed_initialization(true);
   ReturnDefinition(store);
@@ skipping 847 matching lines @@
   Report::MessageF(Report::kBailout,
                    Script::Handle(function.script()),
                    function.token_pos(),
                    "FlowGraphBuilder Bailout: %s %s",
                    String::Handle(function.name()).ToCString(),
                    reason);
   UNREACHABLE();
 }
 
 }  // namespace dart