dart2js cps: Better 'is int' checks.

pkg/compiler/lib/src/js_backend/codegen/codegen.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 code_generator;
 
 import 'glue.dart';
 
 import '../../tree_ir/tree_ir_nodes.dart' as tree_ir;
 import '../../tree_ir/tree_ir_nodes.dart' show BuiltinOperator;
@@ skipping 689 matching lines @@
   js.Expression visitApplyBuiltinOperator(tree_ir.ApplyBuiltinOperator node) {
     List<js.Expression> args = visitExpressionList(node.arguments);
     switch (node.operator) {
       case BuiltinOperator.NumAdd:
         return new js.Binary('+', args[0], args[1]);
       case BuiltinOperator.NumSubtract:
         return new js.Binary('-', args[0], args[1]);
       case BuiltinOperator.NumMultiply:
         return new js.Binary('*', args[0], args[1]);
       case BuiltinOperator.NumAnd:
-        return js.js('(# & #) >>> 0', <js.Expression>[args[0], args[1]]);
+        return js.js('(# & #) >>> 0', args);
       case BuiltinOperator.NumOr:
-        return js.js('(# | #) >>> 0', <js.Expression>[args[0], args[1]]);
+        return js.js('(# | #) >>> 0', args);
       case BuiltinOperator.NumXor:
-        return js.js('(# ^ #) >>> 0', <js.Expression>[args[0], args[1]]);
+        return js.js('(# ^ #) >>> 0', args);
       case BuiltinOperator.NumLt:
         return new js.Binary('<', args[0], args[1]);
       case BuiltinOperator.NumLe:
         return new js.Binary('<=', args[0], args[1]);
       case BuiltinOperator.NumGt:
         return new js.Binary('>', args[0], args[1]);
       case BuiltinOperator.NumGe:
         return new js.Binary('>=', args[0], args[1]);
       case BuiltinOperator.StrictEq:
         return new js.Binary('===', args[0], args[1]);
       case BuiltinOperator.StrictNeq:
         return new js.Binary('!==', args[0], args[1]);
       case BuiltinOperator.LooseEq:
         return new js.Binary('==', args[0], args[1]);
       case BuiltinOperator.LooseNeq:
         return new js.Binary('!=', args[0], args[1]);
       case BuiltinOperator.IsFalsy:
         return new js.Prefix('!', args[0]);
+      case BuiltinOperator.IsNumber:
+        return js.js("typeof # === 'number'", args);
+      case BuiltinOperator.IsNotNumber:
+        return js.js("typeof # !== 'number'", args);
+      case BuiltinOperator.IsFloor:
+        return js.js("Math.floor(#) === #", args);
+      case BuiltinOperator.IsNumberAndFloor:
+        return js.js("typeof # === 'number' && Math.floor(#) === #", args);
     }
   }
 
   visitFunctionExpression(tree_ir.FunctionExpression node) {
     // FunctionExpressions are currently unused.
     // We might need them if we want to emit raw JS nested functions.
     throw 'FunctionExpressions should not be used';
   }
 }