Convert MOD to AND for power-of-two positive constants.

tests/language/modulo_test.dart

Index: tests/language/modulo_test.dart
===================================================================
--- tests/language/modulo_test.dart	(revision 0)
+++ tests/language/modulo_test.dart	(revision 0)
@@ -0,0 +1,30 @@
+// 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.
+// Dart test optimization of modulo oeprator on Smi.
+
+
+main() {
+  for (int i = -3000; i < 3000; i++) {
+    Expect.equals(i % 256, foo(i));
+    Expect.equals(i % -256, boo(i));
+    try {
+      hoo(i);
+      Expect.fail("Exception expected.");
+    } catch (e) {}
+  }
+}
+
+foo(i) {
+  return i % 256;  // This will get optimized to AND instruction.
+}
+
+
+boo(i) {
+  return i % -256;
+}
+
+
+hoo(i) {
+  return i % 0;
+}