bool-property-key.js

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// To prevent constant-folding.

let bTrue = true;

let bFalse = false;

function testMonomorphic() {

  var obj = { true: 1, false: 2 };

  for (var i = 0; i < 40; i++) {

    obj[bTrue] = 1 + obj[bTrue];

    obj[bFalse] = 2 + obj[bFalse];

    var bool = (i & 1) === 1;

    obj[bool] = 3 + obj[bool];

  assertEq(obj.true, 101);

  assertEq(obj.false, 142);

testMonomorphic();

function testMegamorphic() {

  var arr = [];

  for (var i = 0; i < 50; i++) {

    arr.push({ true: i, ["x" + i]: i * 2, false: i * 3 });

  var trues = 0;

  var falses = 0;

  var mixed = 0;

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

    var obj = arr[i % arr.length];

    trues += obj[bTrue];

    falses += obj[bFalse];

    var bool = (i & 1) === 1;

    mixed += obj[bool];

    obj[bool] += 1;

  assertEq(trues, 2475);

  assertEq(falses, 7375);

  assertEq(mixed, 4900);

testMegamorphic();