powerpc: Optimized stpcpy for POWER9

Add stpcpy support to the POWER9 strcpy. This is up to 40% faster on
small strings and up to 90% faster on long relatively unaligned strings,
compared to the POWER8 version. A few examples:

                                        __stpcpy_power9  __stpcpy_power8
Length   20, alignments in bytes  4/ 4:  2.58246          4.8788
Length 1024, alignments in bytes  1/ 6: 24.8186          47.8528

4 files changed, 41 insertions, 6 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index db11345053..61a6901f7d 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -32,7 +32,7 @@ sysdep_routines += memcpy-power8-cached memcpy-power7 memcpy-a2 memcpy-power6 \
 		   strncase-power8
 
 ifneq (,$(filter %le,$(config-machine)))
-sysdep_routines += strcmp-power9 strncmp-power9 strcpy-power9
+sysdep_routines += strcmp-power9 strncmp-power9 strcpy-power9 stpcpy-power9
 endif
 CFLAGS-strncase-power7.c += -mcpu=power7 -funroll-loops
 CFLAGS-strncase_l-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 ad11ede20e..8021d8d8fa 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -98,6 +98,10 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   /* Support sysdeps/powerpc/powerpc64/multiarch/stpcpy.c.  */
   IFUNC_IMPL (i, name, stpcpy,
+#ifdef __LITTLE_ENDIAN__
+	      IFUNC_IMPL_ADD (array, i, strncmp, hwcap2 & PPC_FEATURE2_ARCH_3_00,
+			      __stpcpy_power9)
+#endif
 	      IFUNC_IMPL_ADD (array, i, stpcpy, hwcap2 & PPC_FEATURE2_ARCH_2_07,
 			      __stpcpy_power8)
 	      IFUNC_IMPL_ADD (array, i, stpcpy, hwcap & PPC_FEATURE_HAS_VSX,
diff --git a/sysdeps/powerpc/powerpc64/multiarch/stpcpy-power9.S b/sysdeps/powerpc/powerpc64/multiarch/stpcpy-power9.S
new file mode 100644
index 0000000000..a728d49fd2
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/stpcpy-power9.S
@@ -0,0 +1,24 @@
+/* Optimized stpcpy implementation for POWER9/PPC64.
+   Copyright (C) 2015-2020 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/>.  */
+
+#define STPCPY __stpcpy_power9
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#include <sysdeps/powerpc/powerpc64/le/power9/stpcpy.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/stpcpy.c b/sysdeps/powerpc/powerpc64/multiarch/stpcpy.c
index 0a63c8f51a..68e1e648c3 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/stpcpy.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/stpcpy.c
@@ -26,13 +26,20 @@
 extern __typeof (__stpcpy) __stpcpy_ppc attribute_hidden;
 extern __typeof (__stpcpy) __stpcpy_power7 attribute_hidden;
 extern __typeof (__stpcpy) __stpcpy_power8 attribute_hidden;
+# ifdef __LITTLE_ENDIAN__
+extern __typeof (__stpcpy) __stpcpy_power9 attribute_hidden;
+# endif
 
 libc_ifunc_hidden (__stpcpy, __stpcpy,
-		   (hwcap2 & PPC_FEATURE2_ARCH_2_07)
-		   ? __stpcpy_power8
-		   : (hwcap & PPC_FEATURE_HAS_VSX)
-		     ? __stpcpy_power7
-		     : __stpcpy_ppc);
+# ifdef __LITTLE_ENDIAN__
+		   (hwcap2 & PPC_FEATURE2_ARCH_3_00)
+		   ? __stpcpy_power9 :
+# endif
+		     (hwcap2 & PPC_FEATURE2_ARCH_2_07)
+		     ? __stpcpy_power8
+		     : (hwcap & PPC_FEATURE_HAS_VSX)
+		       ? __stpcpy_power7
+		       : __stpcpy_ppc);
 
 weak_alias (__stpcpy, stpcpy)
 libc_hidden_def (__stpcpy)