ext/standard: Optimize array_column()

[LamentXU123]

Just move some numeric-string key normalization stuff out of the main loop. Also return early for empty input.

Column selector	Reduction
'id'	6.5%
'0'	29.6%
'123456789'	58.6%

[devnexen]

nit: If I were you, I would put inside each case instead wdyt ?

[devnexen]

did you benchmark when the key is not interned string btw ?

[LamentXU123]

did you benchmark when the key is not interned string btw ?

The old benchmarks is already running on non-interned keys.

[devnexen]

can you benchmark this one (esp K2 case) ?

<?php
$case = $argv[1];
$N = 200000;
$rt = substr('xid', 1);

$rows = [];
for ($i = 0; $i < $N; $i++) {
    $rows[] = ($case === 'K3' || $case === 'K4') ? [$rt => $i] : ['id' => $i];
}
$col = ($case === 'K2' || $case === 'K4') ? $rt : 'id';

$t = [];
for ($r = 0; $r < 25; $r++) {
    $s = hrtime(true);
    $out = array_column($rows, $col);
    $t[] = (hrtime(true) - $s) / 1e6;
    unset($out);
}
sort($t);
printf("%.3f\n", $t[12]);

[LamentXU123]

K2 observes ~14% improvements and K3 ~8%. Others are within noise

[devnexen]

not as good locally (~2% for K2) but it s all positive regardless.

[LamentXU123]

Yeah I am away from productive server testing this stuff on personal PC. So perhaps bigger noise than expected.

[LamentXU123]

Thanks!