Unrolled Loop Test (v5)

Revision 5 of this benchmark created by naugtur on

Preparation HTML

<script>
  var data = (function() {
  
    var arr = [],
        i;
  
    for (i = 0; i < 10000; i += 1) {
      arr.push(Math.random());
    }
  
    return arr;
  }());
</script>

Test runner

Ready to run.

Testing in
TestOps/sec
Rolled
var i, max = 0,
    len = data.length;

for (i = 0; i < len; i += 1) {
  if (data[i] > max) {
    max = data[i];
  }
}
ready
Unrolled
var i, max = 0,
    len = data.length;

for (i = 0; i < len; i += 10) {
  if (data[i] > max) {
    max = data[i];
  }
  if (data[i + 1] > max) {
    max = data[i + 1];
  }
  if (data[i + 2] > max) {
    max = data[i + 2];
  }
  if (data[i + 3] > max) {
    max = data[i + 3];
  }
  if (data[i + 4] > max) {
    max = data[i + 4];
  }
  if (data[i + 5] > max) {
    max = data[i + 5];
  }
  if (data[i + 6] > max) {
    max = data[i + 6];
  }
  if (data[i + 7] > max) {
    max = data[i + 7];
  }
  if (data[i + 8] > max) {
    max = data[i + 8];
  }
  if (data[i + 9] > max) {
    max = data[i + 9];
  }
}
ready
Unrolled from both sides
var i, j, max = 0,
    len = data.length;

for (i = 0, j = len - 1; i <= j; i += 1, j -= 1) {
  if (data[i] > max) {
    max = data[i];
  }
  if (data[j] > max) {
    max = data[j];
  }
}
ready
Rolled worst case
var max = 0;


for (var i = 0; i < data.length; i += 1) {
  if (data[i] > max) {
    max = data[i];
  }
}
ready

Revisions

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