Use SAR for positive divident by a power-of two constant divisor.

tests/language/div_with_power_of_two_test.dart

Index: tests/language/div_with_power_of_two_test.dart
===================================================================
--- tests/language/div_with_power_of_two_test.dart	(revision 0)
+++ tests/language/div_with_power_of_two_test.dart	(revision 0)
@@ -0,0 +1,103 @@
+// Copyright (c) 2013, 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.
+// Test division by power of two.
+// Test that results before and after optimization are the same.
+
+// [function, [list of tuples argument/result]].
+var expectedResults =
+  [ [divBy1,
+      [[134217730, 134217730],
+       [-134217730, -134217730],
+       [10, 10],
+       [-10, -10]]],
+    [divByNeg1,
+      [[134217730, -134217730],
+       [-134217730, 134217730],
+       [10, -10],
+       [-10, 10]]],
+    [divBy2,
+      [[134217730, 67108865],
+       [-134217730, -67108865],
+       [10, 5],
+       [-10, -5]]],
+    [divByNeg2,
+      [[134217730, -67108865],
+       [-134217730, 67108865],
+       [10, -5],
+       [-10, 5]]],
+    [divBy4,
+      [[134217730, 33554432],
+       [-134217730, -33554432],
+       [10, 2],
+       [-10, -2]]],
+    [divByNeg4,
+      [[134217730, -33554432],
+       [-134217730, 33554432],
+       [10, -2],
+       [-10, 2]]],
+    [divBy134217728,
+      [[134217730, 1],
+       [-134217730, -1],
+       [10, 0],
+       [-10, 0]]],
+    [divByNeg134217728,
+      [[134217730, -1],
+       [-134217730, 1],
+       [10, 0],
+       [-10, 0]]],
+    // Use different functions for 64 bit arguments.
+    [divBy4_,
+      [[549755813990, 137438953497],
+       [-549755813990, -137438953497],
+       [288230925907525632, 72057731476881408],
+       [-288230925907525632, -72057731476881408]]],
+    [divByNeg4_,
+      [[549755813990, -137438953497],
+       [-549755813990, 137438953497],
+       [288230925907525632, -72057731476881408],
+       [-288230925907525632, 72057731476881408]]],
+    [divBy549755813888,
+      [[549755813990, 1],
+       [-549755813990, -1],
+       [288230925907525632, 524289],
+       [-288230925907525632, -524289]]],
+    [divByNeg549755813888,
+      [[549755813990, -1],
+       [-549755813990, 1],
+       [288230925907525632, -524289],
+       [-288230925907525632, 524289]]],
+  ];
+
+divBy0(a) => a ~/ 0;
+divBy1(a) => a ~/ 1;
+divByNeg1(a) => a ~/ -1;
+divBy2(a) => a ~/ 2;
+divByNeg2(a) => a ~/ -2;
+divBy4(a) => a ~/ 4;
+divByNeg4(a) => a ~/ -4;
+divBy134217728(a) => a ~/ 134217728;
+divByNeg134217728(a) => a ~/ -134217728;
+
+divBy4_(a) => a ~/ 4;
+divByNeg4_(a) => a ~/ -4;
+divBy549755813888(a) => a ~/ 549755813888;
+divByNeg549755813888(a) => a ~/ -549755813888;
+
+main() {
+  for (int i = 0; i < 8000; i++) {
+    for (var e in expectedResults) {
+      Function f = e[0];
+      List values = e[1];
+      for (var v in values) {
+        int arg = v[0];
+        int res = v[1];
+        Expect.equals(res, f(arg));
+      }
+    }
+    try {
+      divBy0(4);
+      Expect.fail("Should have thrown exception.");
+    } on IntegerDivisionByZeroException catch (e) {}
+  }
+}