Optimize DateTime properties

tests/compiler/dart2js/tdiv_test.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 tdiv_test;
+
+import 'dart:async';
+import 'package:expect/expect.dart';
+import 'package:async_helper/async_helper.dart';
+import 'compiler_helper.dart';
+
+const String TEST1 = r"""
+foo(param) {
+  var a = param ? 0xFFFFFFFF : 1;
+  return a ~/ 2;
+  // Above can be compiled to division followed by truncate.
+  // present: ' / 2 | 0'
+  // absent: 'tdiv'
+}
+""";
+
+const String TEST2 = r"""
+foo(param) {
+  var a = param ? 0xFFFFFFFF : 1;
+  return a ~/ 3;
+  // Above can be compiled to division followed by truncate.
+  // present: ' / 3 | 0'
+  // absent: 'tdiv'
+}
+""";
+
+const String TEST3 = r"""
+foo(param) {
+  var a = param ? 0xFFFFFFFF : -1;
+  return a ~/ 2;
+  // Potentially negative inputs go via fast helper.
+  // present: '_tdivFast'
+  // absent: '/'
+}
+""";
+
+const String TEST4 = r"""
+foo(param1, param2) {
+  var a = param1 ? 0xFFFFFFFF : 0;
+  return a ~/ param2;
+  // Unknown divisor goes via full implementation.
+  // present: '$tdiv'
+  // absent: '/'
+}
+""";
+
+const String TEST5 = r"""
+foo(param1, param2) {
+  var a = param1 ? 0xFFFFFFFF : 0;
+  var b = param2 ? 3 : 4;
+  return a ~/ param2;
+  // We could optimize this with range analysis, but type inference summarizes
+  // '3 or 4' to uint31, which is not >= 2.
+  // present: '$tdiv'
+  // absent: '/'
+}
+""";
+
+main() {
+  RegExp directivePattern = new RegExp(
+      //      \1                    \2        \3
+      r'''// *(present|absent): (?:"([^"]*)"|'([^'']*)')''',
+      multiLine: true);
+
+  Future check(String test) {
+    return compile(test, entry: 'foo', check: (String generated) {
+      for (Match match in directivePattern.allMatches(test)) {
+        String directive = match.group(1);
+        String pattern = match.groups([2, 3]).where((s) => s != null).single;
+        if (directive == 'present') {
+          Expect.isTrue(generated.contains(pattern),
+              "Cannot find '$pattern' in:\n$generated");
+        } else {
+          assert(directive == 'absent');
+          Expect.isFalse(generated.contains(pattern),
+              "Must not find '$pattern' in:\n$generated");
+        }
+      }
+    });
+  }
+
+  asyncTest(() => Future.wait([
+    check(TEST1),
+    check(TEST2),
+    check(TEST3),
+    check(TEST4),
+    check(TEST5),
+  ]));
+}