updated for version 7.3.1149
Problem:    New regexp engine: Matching plain text could be faster.
Solution:   Detect a plain text match and handle it specifically.  Add
            vim_regfree().
diff --git a/src/window.c b/src/window.c
index 41e7706..881be8b 100644
--- a/src/window.c
+++ b/src/window.c
@@ -6818,7 +6818,7 @@
 	wp->w_match_head = cur->next;
     else
 	prev->next = cur->next;
-    vim_free(cur->match.regprog);
+    vim_regfree(cur->match.regprog);
     vim_free(cur->pattern);
     vim_free(cur);
     redraw_later(SOME_VALID);
@@ -6837,7 +6837,7 @@
     while (wp->w_match_head != NULL)
     {
 	m = wp->w_match_head->next;
-	vim_free(wp->w_match_head->match.regprog);
+	vim_regfree(wp->w_match_head->match.regprog);
 	vim_free(wp->w_match_head->pattern);
 	vim_free(wp->w_match_head);
 	wp->w_match_head = m;