[php-src] Issue #8283: Performance: array_reduce is drastically slower (~1000x) than implementing the same logic with foreach

Issue: https://github.com/php/php-src/issues/8283 Comment Author: iluuu1994 Hi @Firehed! The problem is that you're causing array separation (arrays are copy on write, unless their reference count is 1) when doing @$carry[$item]++;. The array is being copied over and over again for every iteration of array_reduce. The same would happen for code like this: ```php $result = []; foreach ($data as $item) { $dummy = $result; @$result[$item]++; } ``` That code is pretty much equivalent in performance as the array_reduce example. So I'm closing this as not a bug.