powerpc: Optimized strncat for POWER8

With new optimized strnlen for POWER8 [1], this patch adds
strncat for power8 to make use of optimized strlen and strnlen.
This is faster than POWER7 current implementation for larger strings.

Tested on powerpc64 and powerpc64le.

[1] https://sourceware.org/ml/libc-alpha/2017-03/msg00491.html

	* sysdeps/powerpc/powerpc64/multiarch/Makefile (sysdep_routines): Add
	strncat-power8.
	* sysdeps/powerpc/powerpc64/multiarch/strncat.c (strncat): Add
	__strncat_power8 to ifunc list.
	* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
	(strncat): Add __strncat_power8 to list of strncat functions.
	* sysdeps/powerpc/powerpc64/multiarch/strncat-power8.c: New file.

5 files changed, 50 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 52b8d410a0..b310214c74 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2017-04-13  Rajalakshmi Srinivasaraghavan  <raji@linux.vnet.ibm.com>
+
+	* sysdeps/powerpc/powerpc64/multiarch/Makefile (sysdep_routines): Add
+	strncat-power8.
+	* sysdeps/powerpc/powerpc64/multiarch/strncat.c (strncat): Add
+	__strncat_power8 to ifunc list.
+	* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+	(strncat): Add __strncat_power8 to list of strncat functions.
+	* sysdeps/powerpc/powerpc64/multiarch/strncat-power8.c: New file.
+
 2017-04-11  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
 	[BZ #21270]
diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index 38233a72c0..0eb3d0710d 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -15,7 +15,8 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
 		   strchrnul-power8 strchrnul-power7 strchrnul-ppc64 \
 		   strcpy-power8 strcpy-power7 strcpy-ppc64 stpcpy-power8 \
 		   stpcpy-power7 stpcpy-ppc64 \
-		   strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
+		   strrchr-power7 strrchr-ppc64 \
+		   strncat-power8 strncat-power7 strncat-ppc64 \
 		   strncpy-power7 strncpy-ppc64 \
 		   stpncpy-power8 stpncpy-power7 stpncpy-ppc64 \
 		   strcmp-power9 strcmp-power8 strcmp-power7 strcmp-ppc64 \
diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
index 30a013320b..bddec1a6f8 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -292,6 +292,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/powerpc/powerpc64/multiarch/strncat.c.  */
   IFUNC_IMPL (i, name, strncat,
 	      IFUNC_IMPL_ADD (array, i, strncat,
+			      hwcap2 & PPC_FEATURE2_ARCH_2_07,
+			      __strncat_power8)
+	      IFUNC_IMPL_ADD (array, i, strncat,
 			      hwcap & PPC_FEATURE_HAS_VSX,
 			      __strncat_power7)
 	      IFUNC_IMPL_ADD (array, i, strncat, 1,
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncat-power8.c b/sysdeps/powerpc/powerpc64/multiarch/strncat-power8.c
new file mode 100644
index 0000000000..1ec1259b95
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncat-power8.c
@@ -0,0 +1,31 @@
+/* Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/ >.  */
+
+#include <string.h>
+
+#define STRNCAT __strncat_power8
+
+extern __typeof (strncat) __strncat_power8 attribute_hidden;
+extern __typeof (strlen) __strlen_power8 attribute_hidden;
+extern __typeof (strnlen) __strnlen_power8 attribute_hidden;
+extern __typeof (memcpy) __memcpy_power7 attribute_hidden;
+
+#define strlen    __strlen_power8
+#define __strnlen __strnlen_power8
+#define memcpy    __memcpy_power7
+
+#include <string/strncat.c>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncat.c b/sysdeps/powerpc/powerpc64/multiarch/strncat.c
index 1aa5c11ea4..ba3fe5cac4 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/strncat.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncat.c
@@ -23,9 +23,12 @@
 
 extern __typeof (strncat) __strncat_ppc attribute_hidden;
 extern __typeof (strncat) __strncat_power7 attribute_hidden;
+extern __typeof (strncat) __strncat_power8 attribute_hidden;
 
 libc_ifunc (strncat,
-            (hwcap & PPC_FEATURE_HAS_VSX)
+	    (hwcap & PPC_FEATURE2_ARCH_2_07)
+	    ? __strncat_power8
+	    : (hwcap & PPC_FEATURE_HAS_VSX)
             ? __strncat_power7
             : __strncat_ppc);
 #endif