diff --git a/src/regexp.c b/src/regexp.c
index f06e15c..30a604b 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -730,7 +730,7 @@
     int		l = 1;
     char_u	*p = *pp;
 
-    if (p[1] == '=')
+    if (p[1] == '=' && p[2] != NUL)
     {
 	if (has_mbyte)
 	    l = (*mb_ptr2len)(p + 2);