Remove empty p tags for custom shortcodes

functions.php

// Remove empty p tags for custom shortcodes
	add_filter('the_content', 'op_content_filter');
	function op_content_filter($content) {
		// array of custom shortcodes requiring the fix 
		$block = join('|',array('shortcode1'));

		// opening tag
		$rep = preg_replace("/(<p>)?\[($block)(\s[^\]]+)?\](<\/p>|<br \/>)?/","[$2$3]",$content);
		
		// closing tag
		$rep = preg_replace("/(<p>)?\[\/($block)](<\/p>|<br \/>)?/","[/$2]",$rep);

		return $rep;
	}