This code will segfault php 5.5 (for testing/debugging purposes)

segfault.php

<?php

$contents = '/*' . str_repeat('a', 60000) . '*/ Test1';
$contents = preg_replace('<
    \s*([@{}:;,]|\)\s|\s\()\s* |  # Remove whitespace around separators, but keep space around parentheses.
    /\*([^*\\\\]|\*(?!/))+\*/ |   # Remove comments that are not CSS hacks.
    [\n\r]                        # Remove line breaks.
    >x', '\1', $contents);
print $contents;