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<?php $x = 129; $i = 1; $y = 1; $m = microtime(true); for ($i = 1; $i <= 1000; ++$i){ $y = 1 << ceil(log($x, 2)); } echo microtime(true) - $m, "\n\r"; $y = 1; $m = microtime(true); for ($i = 1; $i <= 1000; ++$i){ while ($y < $x) { $y = $y <<1; } } echo microtime(true) - $m, "\n\r";

preferences:
32.99 ms | 402 KiB | 5 Q