From 28bf38743db6656715c5f3221d52467cbac4872f Mon Sep 17 00:00:00 2001
From: Lars Ingebrigtsen <larsi@gnus.org>
Date: Sat, 24 Jul 2021 17:28:10 +0200
Subject: [PATCH] Tweak Fdirectory_append for efficiency

* src/fileio.c (Fdirectory_append): Make slightly more efficient.
---
 src/fileio.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/fileio.c b/src/fileio.c
index a4f08383776..ddce4723f42 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -795,7 +795,8 @@ usage: (record DIRECTORY &rest COMPONENTS) */)
       for (i = 0; i < nargs; i++)
 	{
 	  Lisp_Object arg = args[i];
-	  if (STRING_MULTIBYTE (arg))
+	  /* Use multibyte or all-ASCII strings as is. */
+	  if (STRING_MULTIBYTE (arg) || SCHARS (arg) == SBYTES (arg))
 	    elements[i] = arg;
 	  else
 	    elements[i] = make_multibyte_string (SSDATA (arg), SCHARS (arg),
-- 
2.39.2