Fix equality instruction to switch from checked (polymorphic) to megamorphic state. This helps da…

runtime/vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/flow_graph_optimizer.h"
 #include "vm/locations.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/os.h"
 #include "vm/scopes.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, enable_type_checks);
-
+DECLARE_FLAG(int, max_polymorphic_checks);
 
 Definition::Definition()
     : range_(NULL),
       temp_index_(-1),
       ssa_temp_index_(-1),
       propagated_type_(AbstractType::Handle()),
       propagated_cid_(kIllegalCid),
       input_use_list_(NULL),
       env_use_list_(NULL),
       use_kind_(kValue),  // Phis and parameters rely on this default.
@@ skipping 1032 matching lines @@
   if ((receiver_class_id() == kSmiCid) ||
       (receiver_class_id() == kDoubleCid) ||
       (receiver_class_id() == kNumberCid)) {
     // Known/library equalities that are guaranteed to return Boolean.
     return kBoolCid;
   }
   return kDynamicCid;
 }
 
 
+bool EqualityCompareInstr::IsPolymorphic() const {
+  return HasICData() &&
+      (ic_data()->NumberOfChecks() > 0) &&
+      (ic_data()->NumberOfChecks() <= FLAG_max_polymorphic_checks);
+}
+
+
 RawAbstractType* RelationalOpInstr::CompileType() const {
   if ((operands_class_id() == kSmiCid) ||
       (operands_class_id() == kDoubleCid) ||
       (operands_class_id() == kNumberCid)) {
     // Known/library relational ops that are guaranteed to return Boolean.
     return Type::BoolType();
   }
   return Type::DynamicType();
 }
 
@@ skipping 1476 matching lines @@
   } while (CanonicalizeMaxBoundary(&max) || CanonicalizeMinBoundary(&length));
 
   // Failed to prove that maximum is bounded with array length.
   return false;
 }
 
 
 #undef __
 
 }  // namespace dart