S390: Refactor wcsncmp ifunc handling.

The ifunc handling for wcsncmp is adjusted in order to omit ifunc
variants if those will never be used as the minimum architecture level
already supports newer CPUs by default.

ChangeLog:

	* sysdeps/s390/multiarch/Makefile
	(sysdep_routines): Remove wcsncmp variants.
	* sysdeps/s390/Makefile (sysdep_routines): Add wcsncmp variants.
	* sysdeps/s390/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Refactor ifunc handling for wcsncmp.
	* sysdeps/s390/multiarch/wcsncmp-c.c: Move to ...
	* sysdeps/s390/wcsncmp-c.c: ... here and adjust ifunc handling.
	* sysdeps/s390/multiarch/wcsncmp-vx.S: Move to ...
	* sysdeps/s390/wcsncmp-vx.S: ... here and adjust ifunc handling.
	* sysdeps/s390/multiarch/wcsncmp.c: Move to ...
	* sysdeps/s390/wcsncmp.c: ... here and adjust ifunc handling.
	* sysdeps/s390/ifunc-wcsncmp.h: New file.

7 files changed, 99 insertions, 18 deletions

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index 00398ba6c2..e1253c04be 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -91,5 +91,6 @@ sysdep_routines += wcslen wcslen-vx wcslen-c \
 		   wcpncpy wcpncpy-vx wcpncpy-c \
 		   wcscat wcscat-vx wcscat-c \
 		   wcsncat wcsncat-vx wcsncat-c \
-		   wcscmp wcscmp-vx wcscmp-c
+		   wcscmp wcscmp-vx wcscmp-c \
+		   wcsncmp wcsncmp-vx wcsncmp-c
 endif
diff --git a/sysdeps/s390/ifunc-wcsncmp.h b/sysdeps/s390/ifunc-wcsncmp.h
new file mode 100644
index 0000000000..3a22bc9c12
--- /dev/null
+++ b/sysdeps/s390/ifunc-wcsncmp.h
@@ -0,0 +1,52 @@
+/* wcsncmp variant information on S/390 version.
+   Copyright (C) 2018 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/>.  */
+
+#if defined USE_MULTIARCH && IS_IN (libc)		\
+  && ! defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define HAVE_WCSNCMP_IFUNC	1
+#else
+# define HAVE_WCSNCMP_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_WCSNCMP_IFUNC_AND_VX_SUPPORT HAVE_WCSNCMP_IFUNC
+#else
+# define HAVE_WCSNCMP_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define WCSNCMP_DEFAULT	WCSNCMP_Z13
+# define HAVE_WCSNCMP_C		0
+# define HAVE_WCSNCMP_Z13	1
+#else
+# define WCSNCMP_DEFAULT	WCSNCMP_C
+# define HAVE_WCSNCMP_C		1
+# define HAVE_WCSNCMP_Z13	HAVE_WCSNCMP_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_WCSNCMP_C
+# define WCSNCMP_C		__wcsncmp_c
+#else
+# define WCSNCMP_C		NULL
+#endif
+
+#if HAVE_WCSNCMP_Z13
+# define WCSNCMP_Z13		__wcsncmp_vx
+#else
+# define WCSNCMP_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index 70162d0eaa..d1740fa8e4 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),wcsmbs)
-sysdep_routines += wcsncmp wcsncmp-vx wcsncmp-c \
-		   wcschr wcschr-vx wcschr-c \
+sysdep_routines += wcschr wcschr-vx wcschr-c \
 		   wcschrnul wcschrnul-vx wcschrnul-c \
 		   wcsrchr wcsrchr-vx wcsrchr-c \
 		   wcsspn wcsspn-vx wcsspn-c \
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index f461063c80..8c9e788ae5 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -55,6 +55,7 @@
 #include <ifunc-wcscat.h>
 #include <ifunc-wcsncat.h>
 #include <ifunc-wcscmp.h>
+#include <ifunc-wcsncmp.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -541,6 +542,18 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_WCSCMP_IFUNC  */
 
+#if HAVE_WCSNCMP_IFUNC
+    IFUNC_IMPL (i, name, wcsncmp,
+# if HAVE_WCSNCMP_Z13
+		IFUNC_IMPL_ADD (array, i, wcsncmp,
+				dl_hwcap & HWCAP_S390_VX, WCSNCMP_Z13)
+# endif
+# if HAVE_WCSNCMP_C
+		IFUNC_IMPL_ADD (array, i, wcsncmp, 1, WCSNCMP_C)
+# endif
+		)
+#endif /* HAVE_WCSNCMP_IFUNC  */
+
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
 # define IFUNC_VX_IMPL(FUNC)						\
@@ -549,8 +562,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 			      __##FUNC##_vx)				\
 	      IFUNC_IMPL_ADD (array, i, FUNC, 1, __##FUNC##_c))
 
-  IFUNC_VX_IMPL (wcsncmp);
-
   IFUNC_VX_IMPL (wcschr);
 
   IFUNC_VX_IMPL (wcschrnul);
diff --git a/sysdeps/s390/multiarch/wcsncmp-c.c b/sysdeps/s390/wcsncmp-c.c
index 92ab5e8b50..a9ccb8de82 100644
--- a/sysdeps/s390/multiarch/wcsncmp-c.c
+++ b/sysdeps/s390/wcsncmp-c.c
@@ -16,10 +16,12 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
-# define WCSNCMP  __wcsncmp_c
+#include <ifunc-wcsncmp.h>
+
+#if HAVE_WCSNCMP_C
+# if HAVE_WCSNCMP_IFUNC
+#  define WCSNCMP WCSNCMP_C
+# endif
 
-# include <wchar.h>
-extern __typeof (wcsncmp) __wcsncmp_c;
 # include <wcsmbs/wcsncmp.c>
 #endif
diff --git a/sysdeps/s390/multiarch/wcsncmp-vx.S b/sysdeps/s390/wcsncmp-vx.S
index 34c203bc90..9bdd21acef 100644
--- a/sysdeps/s390/multiarch/wcsncmp-vx.S
+++ b/sysdeps/s390/wcsncmp-vx.S
@@ -16,7 +16,8 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
+#include <ifunc-wcsncmp.h>
+#if HAVE_WCSNCMP_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -37,7 +38,7 @@
    -v17=part of s2
    -v18=index of unequal
 */
-ENTRY(__wcsncmp_vx)
+ENTRY(WCSNCMP_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -173,5 +174,9 @@ ENTRY(__wcsncmp_vx)
 	lghi	%r1,-1
 	locgrl	%r2,%r1
 	br	%r14
-END(__wcsncmp_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+END(WCSNCMP_Z13)
+
+# if ! HAVE_WCSNCMP_IFUNC
+strong_alias (WCSNCMP_Z13, wcsncmp)
+# endif
+#endif
diff --git a/sysdeps/s390/multiarch/wcsncmp.c b/sysdeps/s390/wcsncmp.c
index ee5f08c1e4..101db44591 100644
--- a/sysdeps/s390/multiarch/wcsncmp.c
+++ b/sysdeps/s390/wcsncmp.c
@@ -16,12 +16,23 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
+#include <ifunc-wcsncmp.h>
+
+#if HAVE_WCSNCMP_IFUNC
 # include <wchar.h>
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc2 (__wcsncmp, wcsncmp)
+# if HAVE_WCSNCMP_C
+extern __typeof (wcsncmp) WCSNCMP_C attribute_hidden;
+# endif
+
+# if HAVE_WCSNCMP_Z13
+extern __typeof (wcsncmp) WCSNCMP_Z13 attribute_hidden;
+# endif
 
-#else
-# include <wcsmbs/wcsncmp.c>
-#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+s390_libc_ifunc_expr (wcsncmp, wcsncmp,
+		      (HAVE_WCSNCMP_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? WCSNCMP_Z13
+		      : WCSNCMP_DEFAULT
+		      )
+#endif