array_filter vs for/foreach usage cost

I understand that array_filter() should costs more than for/foreach because it is a function call that call another function for each item, while the for/foreach is a language constructor that works on a way totally different and its optimized for this kind of job. foreach($items as $item) { if(expr($item)) { $result[] = $item } } array_filter($items, function($item) { return expr($item) } ) But there are some possibility to create some runtime optimizer for cases like that, and "understand" that array_filter() should works like for/foreach? JS have some kind of optimization and functions is faster than constructor for cases like that: http://jsben.ch/pZmLf. I have done some benchmarks with a 60 seconds cycle. https://pastebin.com/zGmE4pxm - for/foreach -> 17.06 mi cycles https://pastebin.com/5E2VwHYm - array (prepared function) -> ​5.49 mi cycles (-67.82%)​ https://pastebin.com/jSA9ZBqt - array (prepared var function) -> 3.30 mi cycles (-80.66%) https://pastebin.com/YPdCmphJ - array_filter (inline) -> 3.14 mi cycles (-81.58%) I think that array_filter() cost will keep the same, once that it is a function and I belive that it is already optimized, but the callable could be optimized to "not be a function internally", working like a constructor. And maybe it could be applied to other functions like array_map(). -- David Rodrigues