powerpc: Optimized strncmp for power10

This patch is based on __strcmp_power10.

Improvements from __strncmp_power9:

    1. Uses new POWER10 instructions
       - This code uses lxvp to decrease contention on load
	 by loading 32 bytes per instruction.

    2. Performance implication
       - This version has around 38% better performance on average.
       - Minor performance regression is seen for few small sizes
	 and specific combination of alignments.

Signed-off-by: Amrita H S <amritahs@linux.ibm.com>
Reviewed-by: Peter Bergner <bergner@linux.ibm.com>

4 files changed, 33 insertions, 1 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index a38ff46..b847c19 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -34,7 +34,7 @@ ifneq (,$(filter %le,$(config-machine)))
 sysdep_routines += memchr-power10 memcmp-power10 memcpy-power10 \
 		   memmove-power10 memset-power10 rawmemchr-power9 \
 		   rawmemchr-power10 strcmp-power9 strcmp-power10 \
-		   strncmp-power9 strcpy-power9 stpcpy-power9 \
+		   strncmp-power9 strncmp-power10 strcpy-power9 stpcpy-power9 \
 		   strlen-power9 strncpy-power9 stpncpy-power9 strlen-power10
 endif
 CFLAGS-strncase-power7.c += -mcpu=power7 -funroll-loops
diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
index 30fd89e..2bb47d3 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -164,6 +164,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   /* Support sysdeps/powerpc/powerpc64/multiarch/strncmp.c.  */
   IFUNC_IMPL (i, name, strncmp,
 #ifdef __LITTLE_ENDIAN__
+	      IFUNC_IMPL_ADD (array, i, strncmp, hwcap2 & PPC_FEATURE2_ARCH_3_1
+			      && hwcap & PPC_FEATURE_HAS_VSX,
+			      __strncmp_power10)
 	      IFUNC_IMPL_ADD (array, i, strncmp, hwcap2 & PPC_FEATURE2_ARCH_3_00
 			      && hwcap & PPC_FEATURE_HAS_ALTIVEC,
 			      __strncmp_power9)
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncmp-power10.S b/sysdeps/powerpc/powerpc64/multiarch/strncmp-power10.S
new file mode 100644
index 0000000..d7026c1
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncmp-power10.S
@@ -0,0 +1,25 @@
+/* Copyright (C) 2024 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
+   <https://www.gnu.org/licenses/>.  */
+
+#if defined __LITTLE_ENDIAN__ && IS_IN (libc)
+#define STRNCMP __strncmp_power10
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#include <sysdeps/powerpc/powerpc64/le/power10/strncmp.S>
+#endif
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncmp.c b/sysdeps/powerpc/powerpc64/multiarch/strncmp.c
index 6178f4a..a5ed67f 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/strncmp.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncmp.c
@@ -29,6 +29,7 @@ extern __typeof (strncmp) __strncmp_ppc attribute_hidden;
 extern __typeof (strncmp) __strncmp_power8 attribute_hidden;
 # ifdef __LITTLE_ENDIAN__
 extern __typeof (strncmp) __strncmp_power9 attribute_hidden;
+extern __typeof (strncmp) __strncmp_power10 attribute_hidden;
 # endif
 # undef strncmp
 
@@ -36,6 +37,9 @@ extern __typeof (strncmp) __strncmp_power9 attribute_hidden;
    ifunc symbol properly.  */
 libc_ifunc_redirected (__redirect_strncmp, strncmp,
 # ifdef __LITTLE_ENDIAN__
+			(hwcap2 & PPC_FEATURE2_ARCH_3_1
+			 && hwcap & PPC_FEATURE_HAS_VSX)
+			? __strncmp_power10 :
 			(hwcap2 & PPC_FEATURE2_ARCH_3_00
 			 && hwcap & PPC_FEATURE_HAS_ALTIVEC)
 			? __strncmp_power9 :