Optimize DateTime properties

pkg/compiler/lib/src/ssa/codegen.dart

 // 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.
 
 part of ssa;
 
 class SsaCodeGeneratorTask extends CompilerTask {
 
   final JavaScriptBackend backend;
   final SourceInformationFactory sourceInformationFactory;
@@ skipping 1266 matching lines @@
   visitMultiply(HMultiply node)     => visitInvokeBinary(node, '*');
   visitSubtract(HSubtract node)     => visitInvokeBinary(node, '-');
   visitBitAnd(HBitAnd node)         => visitBitInvokeBinary(node, '&');
   visitBitNot(HBitNot node)         => visitBitInvokeUnary(node, '~');
   visitBitOr(HBitOr node)           => visitBitInvokeBinary(node, '|');
   visitBitXor(HBitXor node)         => visitBitInvokeBinary(node, '^');
   visitShiftLeft(HShiftLeft node)   => visitBitInvokeBinary(node, '<<');
   visitShiftRight(HShiftRight node) => visitBitInvokeBinary(node, '>>>');
 
   visitTruncatingDivide(HTruncatingDivide node) {
-    assert(node.left.isUInt31(compiler));
+    assert(node.isUInt31(compiler));
+    assert(node.left.isUInt32(compiler));
     assert(node.right.isPositiveInteger(compiler));
     use(node.left);
     js.Expression jsLeft = pop();
     use(node.right);
     push(new js.Binary('/', jsLeft, pop()), node);
     push(new js.Binary('|', pop(), new js.LiteralNumber("0")), node);
   }
 
   visitNegate(HNegate node)         => visitInvokeUnary(node, '-');
 
@@ skipping 1427 matching lines @@
   js.PropertyAccess accessHelper(String name) {
     Element helper = backend.findHelper(name);
     if (helper == null) {
       // For mocked-up tests.
       return js.js('(void 0).$name');
     }
     registry.registerStaticUse(helper);
     return backend.emitter.staticFunctionAccess(helper);
   }
 }