Index: wp-includes/comment.php
===================================================================
--- wp-includes/comment.php	(revision 5864)
+++ wp-includes/comment.php	(working copy)
@@ -500,17 +500,21 @@
 	$post_id = (int) $post_id;
 	if ( !$post_id )
 		return false;
-	$count = $wpdb->get_var("SELECT COUNT(*) FROM $wpdb->comments WHERE comment_post_ID = '$post_id' AND comment_approved = '1'");
-	$wpdb->query("UPDATE $wpdb->posts SET comment_count = $count WHERE ID = '$post_id'");
-	$comment_count_cache[$post_id] = $count;
+	if ( !$post = get_post($post_id) )
+		return false;
 
-	$post = get_post($post_id);
+	$old = (int) $post->comment_count;
+	$new = (int) $wpdb->get_var("SELECT COUNT(*) FROM $wpdb->comments WHERE comment_post_ID = '$post_id' AND comment_approved = '1'");
+	$wpdb->query("UPDATE $wpdb->posts SET comment_count = '$new' WHERE ID = '$post_id'");
+	$comment_count_cache[$post_id] = $new;
+
 	if ( 'page' == $post->post_type )
 		clean_page_cache( $post_id );
 	else
 		clean_post_cache( $post_id );
 
-	do_action('edit_post', $post_id);
+	do_action('wp_update_comment_count', $post_id, $new, $old);
+	do_action('edit_post', $post_id, $post);
 
 	return true;
 }
@@ -816,4 +820,4 @@
 		wp_cache_add($comment->comment_ID, $comment, 'comment');
 }
 
-?>
\ No newline at end of file
+?>