The Tor Browser / file revision

 // |jit-test|

 // Only fails with Ion.

 function add_xors_1() {

     var res = 0;

     var step = 4;

     for (var i = 0x7fffffff | 0; i >= (1 << step); i -= (i >> step)) {

         var x = i ^ (i << 1);

         res += (((x + x) + res + res) | 0);

     }

     return res;

 }

 var r1 = add_xors_1();

 for (var i = 0; i < 100; i++) {

     var r2 = add_xors_1();

     assertEq(r2, r1);

 }

 // Only fails with JM

 function add_xors_2() {

     var res = 0;

     var step = 4;

     for (var i = 0x7fffffff | 0; i >= (1 << step); i -= (i >> step)) {

         var x = i ^ (i << 1);

         res += ((x + x) + res + res) | 0;

     }

     return res;

 }

 var r1 = add_xors_2();

 for (var i = 0; i < 100; i++) {

     var r2 = add_xors_2();

     assertEq(r1, r2);

 }