dart2js cps: Introduce some built-in operators in type propagation.

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

Index: pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart
diff --git a/pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart b/pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart
index 5dbf8c749a8982a9ce603d7a353a808781dd4ed7..8b2b173d448ed519d167aa6752d618dbc29fc4c2 100644
--- a/pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart
+++ b/pkg/compiler/lib/src/cps_ir/cps_ir_tracer.dart
@@ -371,6 +371,12 @@ class IRTracer extends TracerUtil implements cps_ir.Visitor {
     String args = node.typeArguments.map(formatReference).join(', ');
     return "TypeTest ($value ${node.type} ($args))";
   }
+
+  visitApplyBuiltinOperator(cps_ir.ApplyBuiltinOperator node) {
+    String operator = node.operator.toString();
+    String args = node.arguments.map(formatReference).join(', ');
+    return 'ApplyBuiltinOperator $operator ($args)';

[sra1, 2015/06/10 21:07:37]

Small nits:
1. You should almost always use interpolation instead of toString().
2. It is hardly worth having an extra local when you can write

  return 'ApplyBuiltinOperator ${node.operator} ($args)';

+  }
 }
 
 /**
@@ -596,28 +602,25 @@ class BlockCollector implements cps_ir.Visitor {
   visitInterceptor(cps_ir.Interceptor node) {
     unexpectedNode(node);
   }
-
   visitReadTypeVariable(cps_ir.ReadTypeVariable node) {
     unexpectedNode(node);
   }
-
   visitReifyRuntimeType(cps_ir.ReifyRuntimeType node) {
     unexpectedNode(node);
   }
-
   visitTypeExpression(cps_ir.TypeExpression node) {
     unexpectedNode(node);
   }
-
   visitNonTailThrow(cps_ir.NonTailThrow node) {
     unexpectedNode(node);
   }
-
   visitCreateInvocationMirror(cps_ir.CreateInvocationMirror node) {
     unexpectedNode(node);
   }
-
   visitTypeTest(cps_ir.TypeTest node) {
     unexpectedNode(node);
   }
+  visitApplyBuiltinOperator(cps_ir.ApplyBuiltinOperator node) {
+    unexpectedNode(node);
+  }
 }