diff --git a/src/regexp.c b/src/regexp.c
index 1ff5a06..f8b8616 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -3177,7 +3177,7 @@
      * can't go before line 1 */
     if (reg_firstlnum + lnum < 1)
 	return NULL;
-    if (reg_firstlnum + lnum > reg_buf->b_ml.ml_line_count)
+    if (lnum > reg_maxline)
 	/* Must have matched the "\n" in the last line. */
 	return (char_u *)"";
     return ml_get_buf(reg_buf, reg_firstlnum + lnum, FALSE);