Run results for: legacy vs ir-3

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; ONEPLUS A6000) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.181 Mobile Safari/537.36

Browser: Chrome Mobile 88

Operating system: Android

Device Platform: Mobile

Date tested: 3 years ago

Test name	Executions per second
legacy	293512.7 Ops/sec
ir	1100.6 Ops/sec

Script Preparation code:

function isJsArray(obj_0) {
    var tmp0_unsafeCast_0 = Array.isArray(obj_0);
    return tmp0_unsafeCast_0;
  }

function isArray(obj_0) {
    var tmp;
    if (isJsArray(obj_0)) {
      tmp = !obj_0.$type$;
    } else {
      tmp = false;
    }
    return tmp;
  }

function arrayConcat(args) {
    var len = args.length;
    var tmp0_unsafeCast_0 = Array(len);
    var typed = tmp0_unsafeCast_0;
    var inductionVariable = 0;
    var last = len - 1 | 0;
    if (inductionVariable <= last)
      do {
        var i = inductionVariable;
        inductionVariable = inductionVariable + 1 | 0;
        var arr = args[i];
        if (!(!(arr == null) ? isArray(arr) : false)) {
          typed[i] = [].slice.call(arr);
        } else {
          {
            typed[i] = arr;
          }
        }
      }
       while (!(i === last));
    return [].concat.apply([], typed);
  }

var args = (new Int32Array(10000)).map(_ => Math.random(1000000));

Tests:

legacy
arrayConcat([0, 1], args)
ir
[].concat.apply([], [[0, 1], [].slice.call(args)]);