From 79287d783c72f95eb47c26dbfdfca279086e16a9 Mon Sep 17 00:00:00 2001
From: Getz Mikalsen <getz@FreeBSD.org>
Date: Mon, 26 Aug 2024 20:14:15 +0200
Subject: [PATCH] lib/libc/aarch64/string: strcat enable use of SIMD

Call into SIMD strlen and stpcpy for an optimized strcat. Port of
D42600 for amd64.

Tested by:	fuz (exprun)
Reviewed by:	fuz, emaste
Sponsored by:	Google LLC (GSoC 2024)
PR:		281175
Differential Revision: https://reviews.freebsd.org/D46417
---
 lib/libc/aarch64/string/Makefile.inc |  3 ++-
 lib/libc/aarch64/string/strcat.c     | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 lib/libc/aarch64/string/strcat.c

diff --git a/lib/libc/aarch64/string/Makefile.inc b/lib/libc/aarch64/string/Makefile.inc
index 996a2fd45bc..0b297494738 100644
--- a/lib/libc/aarch64/string/Makefile.inc
+++ b/lib/libc/aarch64/string/Makefile.inc
@@ -25,7 +25,8 @@ MDSRCS+= \
 	strspn.S \
 	strcspn.S \
 	strpbrk.c \
-	strsep.c
+	strsep.c \
+	strcat.c
 
 #
 # Add the above functions. Generate an asm file that includes the needed
diff --git a/lib/libc/aarch64/string/strcat.c b/lib/libc/aarch64/string/strcat.c
new file mode 100644
index 00000000000..c70875be1c1
--- /dev/null
+++ b/lib/libc/aarch64/string/strcat.c
@@ -0,0 +1,20 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2024 Getz Mikalsen <getz@FreeBSD.org>
+*/
+
+#include <string.h>
+
+#undef strcat	/* _FORTIFY_SOURCE */
+
+char *
+strcat(char * __restrict s, const char * __restrict append)
+{
+	char *save = s;
+
+	/* call into SIMD optimized functions */
+	stpcpy(s + strlen(s), append);
+
+	return(save);
+}