undefined optimizer behavior #21227

<?php
function f_1() {
    $obj->a = 3;
    $blank_line = <<<EOT


    EOT;
    $array_default_key = array('one',       2,            'three', '4');
    $dom = DOM\HTMLDocument::createFromString('<p>foo</p>', LIBXML_NOERROR);
    $test = function($a = 'a', $b = 'b', $c = 'c') {
        echo "a = $a, b = $b, c = $c\n";
    };
    $dom = new DOMDocument;
    $comment = $dom->createComment("foobarbaz");
    for ($i_2 = 0; $i_2 < 10; $i_2++) {
        $obj = $reflector->newLazyProxy(function ($obj) {
            var_dump("initializer");
            return new C();
        });
        $tStamp = mktime (17, 17, 17, 1, 4099, 1970);
        $x = "foo";
        $step = function () {
            throw new Exception();
        };
        $a = 30;
        $it = new RecursiveArrayIterator([[1]]);
        $objs = [];
        $obj = new stdClass;
        $objs[] = $obj;
        $table_name = "table_22pg_fetch_object";
        $sql = "SELECT * FROM $table_name WHERE num = 0";
        $pdo = PDOTest::test_factory(__DIR__ . '/common.phpt', Pdo\Pgsql::class, true);
    }
    return $input % 2 === 0;
}