Add fast 64-bit integer ADD and SUB to the optimizing compiler.

runtime/vm/intermediate_language.h

 // 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.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 3520 matching lines @@
     deopt_id_ = instance_call->deopt_id();
   }
 
   Value* left() const { return inputs_[0]; }
   Value* right() const { return inputs_[1]; }
 
   Token::Kind op_kind() const { return op_kind_; }
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const {
+    return (op_kind() == Token::kADD) || (op_kind() == Token::kSUB);
+  }
 
   virtual bool HasSideEffect() const { return false; }
 
   virtual bool AffectedBySideEffect() const { return false; }
 
   virtual bool AttributesEqual(Instruction* other) const {
     return op_kind() == other->AsUnboxedMintBinaryOp()->op_kind();
   }
 
   virtual intptr_t ResultCid() const;
@@ skipping 549 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_