Faster zend sorting implementation

Hey: I was working on zend_qsort improvement. but I got a problem need to be disscussed with you fist.. as we know, previously zend_qsort is not a stable sorting algo. my draft patch (which already get 0.1% IRs reduce in wordpress) is kindof a stable sorting algo, you can find it here (https://github.com/laruence/php-src/compare/zend_sort) so, there is a bc break, like for : $array = array("o", "O"); sort($array, SORT_STRING|SORT_FLAG_CASE); var_dump($array); previously implementation does the swap: array(2) { [0]=> string(1) "O" [1]=> string(1) "o" } but new implementation doesn't not: array(2) { [0]=> string(1) "o" [1]=> string(1) "O" } do you think such BC break is acceptable? or I still need a RFC? :< thanks -- Xinchen Hui @Laruence http://www.laruence.com/