If a PolymorphicInstanceCall has a single target, ..

runtime/vm/intermediate_language_x64.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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 1949 matching lines @@
 void PolymorphicInstanceCallComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   Label* deopt = compiler->AddDeoptStub(instance_call()->deopt_id(),
                                         instance_call()->try_index(),
                                         kDeoptPolymorphicInstanceCallTestFail);
   if (!HasICData() || (ic_data()->NumberOfChecks() == 0)) {
     __ jmp(deopt);
     return;
   }
   ASSERT(HasICData());
   ASSERT(ic_data()->num_args_tested() == 1);
+  if (!with_checks()) {
+    const Function& target = Function::ZoneHandle(ic_data()->GetTargetAt(0));
+    compiler->GenerateStaticCall(instance_call()->deopt_id(),
+                                 instance_call()->token_pos(),
+                                 instance_call()->try_index(),
+                                 target,
+                                 instance_call()->ArgumentCount(),
+                                 instance_call()->argument_names(),
+                                 locs());
+    return;
+  }
   Label handle_smi;
   Label* is_smi_label =
       ic_data()->GetReceiverClassIdAt(0) == kSmiCid ?  &handle_smi : deopt;
 
   // Load receiver into RAX.
   __ movq(RAX,
       Address(RSP, (instance_call()->ArgumentCount() - 1) * kWordSize));
   __ testq(RAX, Immediate(kSmiTagMask));
   __ j(ZERO, is_smi_label);
   Label done;
@@ skipping 223 matching lines @@
   __ testq(value, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, deopt);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64