Equality can be converted to a strict equality with checks. If the number of checks exceeds the thr…

runtime/vm/intermediate_language.cc

 // Copyright (c) 2013, 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/bigint_operations.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 {
 
+DEFINE_FLAG(int, max_equality_polymorphic_checks, 32,
+    "Maximum number of polymorphic checks in equality operator,"
+    " otherwise use megamorphic dispatch.");
 DEFINE_FLAG(bool, new_identity_spec, true,
     "Use new identity check rules for numbers.");
 DEFINE_FLAG(bool, propagate_ic_data, true,
     "Propagate IC data from unoptimized to optimized IC calls.");
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, eliminate_type_checks);
 DECLARE_FLAG(int, max_polymorphic_checks);
 DECLARE_FLAG(bool, trace_optimization);
 DECLARE_FLAG(bool, trace_constant_propagation);
 DECLARE_FLAG(bool, throw_on_javascript_int_overflow);
@@ skipping 993 matching lines @@
 }
 
 
 bool EqualityCompareInstr::IsPolymorphic() const {
   return HasICData() &&
       (ic_data()->NumberOfChecks() > 0) &&
       (ic_data()->NumberOfChecks() <= FLAG_max_polymorphic_checks);
 }
 
 
+bool EqualityCompareInstr::IsCheckedStrictEqual() const {
+  if (!HasICData()) return false;
+  return ic_data()->AllTargetsHaveSameOwner(kInstanceCid) &&
+         (unary_ic_data_->NumberOfChecks() <=
+             FLAG_max_equality_polymorphic_checks);
+}
+
+
 bool BinarySmiOpInstr::CanDeoptimize() const {
   if (FLAG_throw_on_javascript_int_overflow) return true;
   switch (op_kind()) {
     case Token::kBIT_AND:
     case Token::kBIT_OR:
     case Token::kBIT_XOR:
       return false;
     case Token::kSHR: {
       // Can't deopt if shift-count is known positive.
       Range* right_range = this->right()->definition()->range();
@@ skipping 1516 matching lines @@
     default:
       UNREACHABLE();
   }
   return kPowRuntimeEntry;
 }
 
 
 #undef __
 
 }  // namespace dart