patch 7.4.783
Problem:    copy_chars() and copy_spaces() are inefficient.
Solution:   Use memset() instead. (Dominique Pelle)
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 838354d..610ac86 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -250,7 +250,7 @@
     /* autoindent for :insert and :append */
     if (firstc <= 0)
     {
-	copy_spaces(ccline.cmdbuff, indent);
+	vim_memset(ccline.cmdbuff, ' ', indent);
 	ccline.cmdbuff[indent] = NUL;
 	ccline.cmdpos = indent;
 	ccline.cmdspos = indent;