Fix performance degradation in DeltaBlue. When converting equality to strict-equality...

runtime/vm/flow_graph_optimizer.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/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 2898 matching lines @@
                   current_instruction->env(),
                   current_instruction);
     ASSERT((compare->kind() == Token::kEQ) || (compare->kind() == Token::kNE));
     Token::Kind strict_kind = (compare->kind() == Token::kEQ) ?
         Token::kEQ_STRICT : Token::kNE_STRICT;
     StrictCompareInstr* strict_comp =
         new StrictCompareInstr(compare->token_pos(),
                                strict_kind,
                                compare->left()->Copy(),
                                compare->right()->Copy());
+    // Numbers override equality and are therefore not part of this conversion.
+    strict_comp->set_needs_number_check(false);
     current_instruction->ReplaceWith(strict_comp, current_iterator());
     return true;
   }
   return false;
 }
 
 
 template <typename T>
 void FlowGraphOptimizer::HandleEqualityCompare(EqualityCompareInstr* comp,
                                                T current_instruction) {
@@ skipping 4476 matching lines @@
 
   // Insert materializations at environment uses.
   const Class& cls = Class::Handle(alloc->constructor().Owner());
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, cls, *fields);
   }
 }
 
 
 }  // namespace dart