Dead Code Elimination (DCE) Escape Analysis Sparse Conditional Constant Propagation PHP 7.1 PHP 7.2 Try to trick it PHP 7.2 But... foo = $x; return $x; } ]]> PHP 7.3 foo = $x; return $x; } ]]> PHP 7.3 PHP 7.2 PHP 7.3 PHP 7.3 foo = 0; $i = 1; $c = $i < 2; if ($c) { $k = 2 * $i; $o->foo = $i; echo $o->foo; } $o->foo += 2; $o->foo++; return $o->foo; } ]]> PHP 7.3