run code in 200+ php & hhvm versions
Bugs & Features
<?php class x { $foo = 1; function &retRef() { return $this->foo; } } $c = new x(); $x = $c->retRef(); $x = 2; var_dump($var, $x);

Here you find the average performance (time & memory) of each version. A grayed out version indicates it didn't complete successfully (based on exit-code).
Note: hhvm uses a JIT which only kicks in after a few runs. Since we run scripts only once, hhvm always runs slower.

VersionSystem time (s)User time (s)Memory (MiB)