Bug #75938 [Ver->Csd]: Modulus value not stored in variable

Edit report at https://bugs.php.net/bug.php?id=75938&edit=1 ID: 75938 Updated by: nikic@php.net Reported by: php at darkain dot com Summary: Modulus value not stored in variable -Status: Verified +Status: Closed Type: Bug Package: Scripting Engine problem Operating System: Debian 9.3 PHP Version: 7.2.2 Block user comment: N Private report: N New Comment: Automatic comment on behalf of nikita.ppv@gmail.com Revision: http://git.php.net/?p=php-src.git;a=commit;h=7aac61ce762b2658263f605dd4d910f6914b7129 Log: Fixed bug #75938 Previous Comments: ------------------------------------------------------------------------ [2018-02-08 20:43:45] nikic@php.net Indeed, this is a bug in value range inference. The code handling modulus operations looks pretty bogus to me. ------------------------------------------------------------------------ [2018-02-08 19:55:56] php at darkain dot com Description: ------------ Using this combination of code, $mod remains INT 0 instead of being set to INT 1. The wrapped var_dump however shows the proper value still. I've tested this code on my Debian box with: PHP 7.2.2-1+0~20180205160742.18+stretch~1.gbpb78b58 On my test machine, php cli works properly. However, php fpm shows this particular error. My guess is that this is somewhere in the optimizer. Changing or removing any line prior to the first var_dump will result in proper output. Changing the values from variables to constant will result in proper output. Changing the modulus operator to any other operator will result in a proper output. Test script: --------------- function borken($columns) { $columns = (int) $columns; if ($columns < 1) return 0; $count = count([1,2,3,4,5]); var_dump($mod = ($count % $columns)); var_dump($mod); } borken(2); Expected result: ---------------- int(1) int(1) Actual result: -------------- int(1) int(0) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=75938&edit=1