The Tor Browser / file revision

 // |jit-test| slow;

 // Binary: cache/js-dbg-32-e5e66f40c35b-linux

 // Flags:

 //

 gczeal(2);

 function subset(list, size) {

   if (size == 0 || !list.length)

     return [list.slice(0, 0)];

   var result = [];

   for (var i = 0, n = list.length; i < n; i++) {

     var pick = list.slice(i, i+1);

     var rest = list.slice(0, i).concat(list.slice(i+1));

     for each (var x in subset(rest, size-1))

       result.push(pick.concat(x));

   }

   return result;

 }

 var bops = [

   ["=", "|=", "^=", "&=", "<<=", ">>=", ">>>=", "+=", "-=", "*=", "/=", "%="],

   ];

 var aops = [];

 for (var i = 0; i < bops.length; i++) {

   for (var j = 0; j < bops[i].length; j++) {

     var k = bops[i][j];

     aops.push(k);

 }

 for (i = 2; i < 5; i++) {

   var sets = subset(aops, i);

   }

 }