dart2js cps: More aggressive operator specialization.

pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart

 // Copyright (c) 2014, 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.
 
 library dart2js.ir_tracer;
 
 import 'dart:async' show EventSink;
 import 'cps_ir_nodes.dart' as cps_ir;
 import '../tracer.dart';
 
@@ skipping 375 matching lines @@
     String object = formatReference(node.object);
     String index = node.index == null
         ? 'no-index'
         : formatReference(node.index);
     String length = node.length == null
         ? 'no-length'
         : formatReference(node.length);
     return 'BoundsCheck $object $index $length ${node.checkString}';
   }
 
-  visitNullCheck(cps_ir.NullCheck node) {
+  visitReceiverCheck(cps_ir.ReceiverCheck node) {
     String value = formatReference(node.value);
     String condition = formatReference(node.condition);
-    return 'NullCheck $value condition:$condition selector:${node.selector}';
+    return 'ReceiverCheck $value $condition ${node.selector} '
+        '${node.flagString}';
   }
 }
 
 /**
  * Invents (and remembers) names for Continuations, Parameters, etc.
  * The names must match the conventions used by IR Hydra, e.g.
  * Continuations and Functions must have names of form B### since they
  * are visualized as basic blocks.
  */
 class Names {
@@ skipping 264 matching lines @@
   }
 
   visitRefinement(cps_ir.Refinement node) {
     unexpectedNode(node);
   }
 
   visitBoundsCheck(cps_ir.BoundsCheck node) {
     unexpectedNode(node);
   }
 
-  visitNullCheck(cps_ir.NullCheck node) {
+  visitReceiverCheck(cps_ir.ReceiverCheck node) {
     unexpectedNode(node);
   }
 }