Index: modules/filter/filter.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/filter/filter.module,v
retrieving revision 1.190
diff -u -p -r1.190 filter.module
--- modules/filter/filter.module	22 Oct 2007 10:32:03 -0000	1.190
+++ modules/filter/filter.module	26 Oct 2007 01:25:47 -0000
@@ -900,6 +900,7 @@ function _filter_autop($text) {
       $chunk = preg_replace("/\n\n+/", "\n\n", $chunk); // take care of duplicates
       $chunk = preg_replace('/\n?(.+?)(?:\n\s*\n|\z)/s', "<p>$1</p>\n", $chunk); // make paragraphs, including one at the end
       $chunk = preg_replace('|<p>\s*</p>\n|', '', $chunk); // under certain strange conditions it could create a P of entirely whitespace
+      $chunk = preg_replace('|<p>(<hr[^>]*>)</p>|', "$1", $chunk); // don't wrap hr
       $chunk = preg_replace("|<p>(<li.+?)</p>|", "$1", $chunk); // problem with nested lists
       $chunk = preg_replace('|<p><blockquote([^>]*)>|i', "<blockquote$1><p>", $chunk);
       $chunk = str_replace('</blockquote></p>', '</p></blockquote>', $chunk);