Negative numbers should not be >>> shifted.

tests/language/positive_bit_operations_test.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.
 
 constants() {
   Expect.equals(0x80000000, 0x80000000 | 0);
   Expect.equals(0x80000001, 0x80000000 | 1);
   Expect.equals(0x80000000, 0x80000000 | 0x80000000);
   Expect.equals(0xFFFFFFFF, 0xFFFF0000 | 0xFFFF);
   Expect.equals(0x80000000, 0x80000000 & 0xFFFFFFFF);
   Expect.equals(0x80000000, 0x80000000 & 0x80000000);
   Expect.equals(0x80000000, 0x80000000 & 0xF0000000);
   Expect.equals(0x80000000, 0xFFFFFFFF & 0x80000000);
   Expect.equals(0x80000000, 0x80000000 ^ 0);
   Expect.equals(0xFFFFFFFF, 0x80000000 ^ 0x7FFFFFFF);
   Expect.equals(0xFFFFFFFF, 0x7FFFFFFF ^ 0x80000000);
   Expect.equals(0xF0000000, 0x70000000 ^ 0x80000000);
   Expect.equals(0x80000000, 1 << 31);
   Expect.equals(0xFFFFFFF0, 0xFFFFFFF << 4);
   Expect.equals(0x7FFFFFFF, 0xFFFFFFFF >> 1);
+  Expect.equals(0xFFFF0000, (-1 >> 16) & 0xFFFF0000);
   Expect.equals(0xFFFFFFFC,
                 ((((((0xFFFFFFF << 4) // 0xFFFFFFF0
                                 >> 1) // 0x7FFFFFF8
                                 | 0x80000000) // 0xFFFFFFF8
                                 >> 2) // 0x3FFFFFFE
                                 ^ 0x40000000) // 0x7FFFFFFE
                                 << 1));
 }
 
 foo(i) {
@@ skipping 22 matching lines @@
   Expect.equals(0x80000000, id(0x80000000) & id(0x80000000));
   Expect.equals(0x80000000, id(0x80000000) & id(0xF0000000));
   Expect.equals(0x80000000, id(0xFFFFFFFF) & id(0x80000000));
   Expect.equals(0x80000000, id(0x80000000) ^ id(0));
   Expect.equals(0xFFFFFFFF, id(0x80000000) ^ id(0x7FFFFFFF));
   Expect.equals(0xFFFFFFFF, id(0x7FFFFFFF) ^ id(0x80000000));
   Expect.equals(0xF0000000, id(0x70000000) ^ id(0x80000000));
   Expect.equals(0x80000000, id(1) << id(31));
   Expect.equals(0xFFFFFFF0, id(0xFFFFFFF) << id(4));
   Expect.equals(0x7FFFFFFF, id(0xFFFFFFFF) >> id(1));
+  Expect.equals(0xFFFF0000, (id(-1) >> 16) & 0xFFFF0000);
   Expect.equals(0xFFFFFFFC,
                 ((((((id(0xFFFFFFF) << 4) // 0xFFFFFFF0
                                     >> 1) // 0x7FFFFFF8
                                     | 0x80000000) // 0xFFFFFFF8
                                     >> 2) // 0x3FFFFFFE
                                     ^ 0x40000000) // 0x7FFFFFFE
                                     << 1));
 }
 
 speculative() {
   var a = id(0x80000000);
   var b = id(0);
   var c = id(1);
   var d = id(0xFFFF0000);
   var e = id(0xFFFF);
   var f = id(0xFFFFFFFF);
   var g = id(0xF0000000);
   var h = id(0x7FFFFFFF);
   var j = id(0x70000000);
   var k = id(31);
   var l = id(4);
   var m = id(0xFFFFFFF);
+  var n = id(-1);
   for (int i = 0; i < 1; i++) {
     Expect.equals(0x80000000, a | b);
     Expect.equals(0x80000001, a | c);
     Expect.equals(0x80000000, a | a);
     Expect.equals(0xFFFFFFFF, d | e);
     Expect.equals(0x80000000, a & f);
     Expect.equals(0x80000000, a & a);
     Expect.equals(0x80000000, a & g);
     Expect.equals(0x80000000, f & a);
     Expect.equals(0x80000000, a ^ b);
     Expect.equals(0xFFFFFFFF, a ^ h);
     Expect.equals(0xFFFFFFFF, h ^ a);
     Expect.equals(0xF0000000, j ^ a);
     Expect.equals(0x80000000, c << k);
     Expect.equals(0xFFFFFFF0, m << l);
     Expect.equals(0x7FFFFFFF, f >> c);
+    Expect.equals(0xFFFF0000, (n >> 16) & 0xFFFF0000);
     Expect.equals(0xFFFFFFFC,
                   ((((((m << 4) // 0xFFFFFFF0
                           >> 1) // 0x7FFFFFF8
                           | 0x80000000) // 0xFFFFFFF8
                           >> 2) // 0x3FFFFFFE
                           ^ 0x40000000) // 0x7FFFFFFE
                           << 1));
   }
 }
 
 // Due to bad precedence rules this example was broken in Dart2Js.
 precedence() {
   Expect.equals(0x80000000, -1 & 0x80000000);
   Expect.equals(0x80000000, id(-1) & 0x80000000);
   Expect.equals(0x80000000, ~(~(0x80000000)));
   Expect.equals(0x80000000, ~(~(id(0x80000000))));
 }
 
 main() {
   constants();
   interceptors();
   speculative();
   precedence();
 }