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JIT if condition optimization leads to flipped result: true is false and false is true #21593
Description
Description
The following code:
<?php declare(strict_types=1);
$a = new stdClass();
$a->a = 'a';
if (!empty($a?->a)) {
echo 'OK';
} else {
echo 'ERROR';
}
echo PHP_EOL;run with:
php -dopcache.enable=1 -dopcache.enable_cli=1 -dopcache.jit=1205 ./file.php
will result in
ERROR
while plain
php ./file.php
will result in
OK
tested with:
docker run --rm -ti -v ./jitIssue.php:/jitIssue.php php:8.5 php -dopcache.enable=1 -dopcache.enable_cli=1 -dopcache.jit=1205 /jitIssue.php
docker run --rm -ti -v ./jitIssue.php:/jitIssue.php php:8.4 php -dopcache.enable=1 -dopcache.enable_cli=1 -dopcache.jit=1205 /jitIssue.php
(it seems php8.3 is not affected)
The issue seems to be a negated empty with a null-safe operator inside, only in an if condition.
if (!empty($a?->a)) => fails
if (empty($a?->a)) => works
if (!empty($a->a)) => works
$result = !empty($a?->a) => works
PHP Version
PHP 8.4.19 (cli) (built: Mar 16 2026 22:25:56) (NTS)
Copyright (c) The PHP Group
Built by https://github.com/docker-library/php
Zend Engine v4.4.19, Copyright (c) Zend Technologies
with Zend OPcache v8.4.19, Copyright (c), by Zend Technologies
and
PHP 8.5.4 (cli) (built: Mar 16 2026 22:25:19) (NTS)
Copyright (c) The PHP Group
Built by https://github.com/docker-library/php
Zend Engine v4.5.4, Copyright (c) Zend Technologies
with Zend OPcache v8.5.4, Copyright (c), by Zend Technologies
Operating System
No response
Activity
iluuu1994 commentedon Apr 1, 2026
Nice reproducer, thanks!
Fix function JIT JMPNZ smart branch
paulmhh commentedon Apr 2, 2026
thank you for the very quick fix and the credits, much appreciated