third_party/WebKit/LayoutTests/fast/js/negate-overflow.html

   1 <p>Test for overflow when negating the largest negative signed int.</p>
   2 <p>If the test passes, you'll see a series of PASS messages below.</p>
   3
   4 <pre id="console"></pre>
   5
   6 <script>
   7 function $(id)
   8 {
   9     return document.getElementById(id);
  10 }
  11
  12 function log(s)
  13 {
  14     $("console").appendChild(document.createTextNode(s + "\n"));
  15 }
  16
  17 function shouldBe(aDescription, a, b)
  18 {
  19     if (a === b) {
  20         log("PASS: " + aDescription + " should be " + b + " and is.");
  21     } else {
  22         log("FAIL: " + aDescription + " should be " + b + " but instead is " + a + ".");
  23     }
  24 }
  25
  26 (function () {
  27     if (window.testRunner)
  28         testRunner.dumpAsText();
  29
  30     // Can be constant-folded by the parser.
  31     var x = -(-2147483648);
  32     shouldBe("x", x, 2147483648);
  33
  34     // Can't be constant-folded without dataflow analysis.
  35     var y = -2147483648;
  36     y = -y;
  37     shouldBe("y", y, 2147483648);
  38 })();
  39 </script>