Partially revert r26703 and omit regular code generation for implicit accessors.

runtime/vm/flow_graph_compiler_x64.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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1012 matching lines @@
     ASSERT(StackSize() >= 0);
     __ Comment("Enter frame");
     __ EnterDartFrame(StackSize() * kWordSize, new_pp);
   }
 }
 
 
 void FlowGraphCompiler::CompileGraph() {
   InitCompiler();
 
-  TryIntrinsify();
+  if (TryIntrinsify()) {
+    // Skip regular code generation.
+    return;
+  }
 
   EmitFrameEntry();
   ASSERT(assembler()->constant_pool_allowed());
 
   const Function& function = parsed_function().function();
 
   const int num_fixed_params = function.num_fixed_parameters();
   const int num_copied_params = parsed_function().num_copied_params();
   const int num_locals = parsed_function().num_stack_locals();
 
@@ skipping 711 matching lines @@
   __ movups(reg, Address(RSP, 0));
   __ AddImmediate(RSP, Immediate(kFpuRegisterSize));
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64