dart2js cps: Combine integer type check with bounds check.

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

 // Copyright (c) 2015, 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 builtin_operator;
 // This is shared by the CPS and Tree IRs.
 // Both cps_ir_nodes and tree_ir_nodes import and re-export this file.
 
 /// An operator supported natively in the CPS and Tree IRs using the
 /// `ApplyBuiltinOperator` instructions.
 ///
@@ skipping 124 matching lines @@
   /// Compiles to `typeof x === 'number' && Math.floor(x) === x`
   IsInteger,
 
   /// Returns true if the argument is not an integer.
   ///
   /// The argument must be repeated 3 times.
   ///
   /// Compiles to `typeof x !== 'number' || Math.floor(x) !== x`
   IsNotInteger,
 
+  /// Returns true if `x` is an unsigned 32-bit integer.
+  ///
+  /// The argument must be repeated 2 times.
+  ///
+  /// Compiles to `x >>> 0 === x`
+  IsUnsigned32BitInteger,
+
+  /// Returns false if `x` is an unsigned 32-bit integer.
+  ///
+  /// The argument must be repeated 2 times.
+  ///
+  /// Compiles to `x >>> 0 !== x`
+  IsNotUnsigned32BitInteger,
+
   /// Returns true if the argument is a fixed length Array.
   ///
   /// Uses one argument.
   ///
   /// Precondition: Argument is a JavaScript Array.
   IsFixedLengthJSArray,
 
   // TODO(sra): Remove this and replace with IsFalsy(IsFixedLengthJSArray(x)).
   IsExtendableJSArray,
 
@@ skipping 41 matching lines @@
     case BuiltinOperator.NumSubtract:
     case BuiltinOperator.NumMultiply:
     case BuiltinOperator.NumDivide:
     case BuiltinOperator.NumRemainder:
     case BuiltinOperator.StringConcatenate:
       return true;
     default:
       return false;
   }
 }