S390: Refactor wmemcmp ifunc handling.

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

7 files changed, 96 insertions, 29 deletions

diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index ae2ae3d2ea..35fcf7e21d 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -100,5 +100,6 @@ sysdep_routines += wcslen wcslen-vx wcslen-c \
 		   wcspbrk wcspbrk-vx wcspbrk-c \
 		   wcscspn wcscspn-vx wcscspn-c \
 		   wmemchr wmemchr-vx wmemchr-c \
-		   wmemset wmemset-vx wmemset-c
+		   wmemset wmemset-vx wmemset-c \
+		   wmemcmp wmemcmp-vx wmemcmp-c
 endif
diff --git a/sysdeps/s390/ifunc-wmemcmp.h b/sysdeps/s390/ifunc-wmemcmp.h
new file mode 100644
index 0000000000..1b38a01459
--- /dev/null
+++ b/sysdeps/s390/ifunc-wmemcmp.h
@@ -0,0 +1,52 @@
+/* wmemcmp 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_WMEMCMP_IFUNC	1
+#else
+# define HAVE_WMEMCMP_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_WMEMCMP_IFUNC_AND_VX_SUPPORT HAVE_WMEMCMP_IFUNC
+#else
+# define HAVE_WMEMCMP_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define WMEMCMP_DEFAULT	WMEMCMP_Z13
+# define HAVE_WMEMCMP_C		0
+# define HAVE_WMEMCMP_Z13	1
+#else
+# define WMEMCMP_DEFAULT	WMEMCMP_C
+# define HAVE_WMEMCMP_C		1
+# define HAVE_WMEMCMP_Z13	HAVE_WMEMCMP_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_WMEMCMP_C
+# define WMEMCMP_C		__wmemcmp_c
+#else
+# define WMEMCMP_C		NULL
+#endif
+
+#if HAVE_WMEMCMP_Z13
+# define WMEMCMP_Z13		__wmemcmp_vx
+#else
+# define WMEMCMP_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index cc6dd7adb1..fec3615304 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,7 +1,3 @@
-ifeq ($(subdir),wcsmbs)
-sysdep_routines += wmemcmp wmemcmp-vx wmemcmp-c
-endif
-
 ifeq ($(subdir),iconvdata)
 override define generate-8bit-table
 $(make-target-directory)
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index 7040959269..177c5fd6fe 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -64,6 +64,7 @@
 #include <ifunc-wcscspn.h>
 #include <ifunc-wmemchr.h>
 #include <ifunc-wmemset.h>
+#include <ifunc-wmemcmp.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -658,17 +659,17 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_WMEMSET_IFUNC  */
 
-#ifdef HAVE_S390_VX_ASM_SUPPORT
-
-# define IFUNC_VX_IMPL(FUNC)						\
-  IFUNC_IMPL (i, name, FUNC,						\
-	      IFUNC_IMPL_ADD (array, i, FUNC, dl_hwcap & HWCAP_S390_VX, \
-			      __##FUNC##_vx)				\
-	      IFUNC_IMPL_ADD (array, i, FUNC, 1, __##FUNC##_c))
-
-  IFUNC_VX_IMPL (wmemcmp);
-
-#endif /* HAVE_S390_VX_ASM_SUPPORT */
+#if HAVE_WMEMCMP_IFUNC
+    IFUNC_IMPL (i, name, wmemcmp,
+# if HAVE_WMEMCMP_Z13
+		IFUNC_IMPL_ADD (array, i, wmemcmp,
+				dl_hwcap & HWCAP_S390_VX, WMEMCMP_Z13)
+# endif
+# if HAVE_WMEMCMP_C
+		IFUNC_IMPL_ADD (array, i, wmemcmp, 1, WMEMCMP_C)
+# endif
+		)
+#endif /* HAVE_WMEMCMP_IFUNC  */
 
   return i;
 }
diff --git a/sysdeps/s390/multiarch/wmemcmp-c.c b/sysdeps/s390/wmemcmp-c.c
index 2fd39d5013..0c73636add 100644
--- a/sysdeps/s390/multiarch/wmemcmp-c.c
+++ b/sysdeps/s390/wmemcmp-c.c
@@ -16,11 +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 WMEMCMP  __wmemcmp_c
+#include <ifunc-wmemcmp.h>
 
-# include <wchar.h>
-extern __typeof (wmemcmp) __wmemcmp_c;
+#if HAVE_WMEMCMP_C
+# if HAVE_WMEMCMP_IFUNC
+#  define WMEMCMP WMEMCMP_C
+# endif
 
 # include <wcsmbs/wmemcmp.c>
 #endif
diff --git a/sysdeps/s390/multiarch/wmemcmp-vx.S b/sysdeps/s390/wmemcmp-vx.S
index e2fc21e419..87ae21b4f1 100644
--- a/sysdeps/s390/multiarch/wmemcmp-vx.S
+++ b/sysdeps/s390/wmemcmp-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-wmemcmp.h>
+#if HAVE_WMEMCMP_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -37,7 +38,7 @@
    -v17=part of s2
    -v18=index of unequal
 */
-ENTRY(__wmemcmp_vx)
+ENTRY(WMEMCMP_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -145,5 +146,9 @@ ENTRY(__wmemcmp_vx)
 	la	%r2,0(%r5,%r2)
 	la	%r3,0(%r5,%r3)
 	j	.Lremaining
-END(__wmemcmp_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+END(WMEMCMP_Z13)
+
+# if ! HAVE_WMEMCMP_IFUNC
+strong_alias (WMEMCMP_Z13, wmemcmp)
+# endif
+#endif
diff --git a/sysdeps/s390/multiarch/wmemcmp.c b/sysdeps/s390/wmemcmp.c
index a4cb440c45..6c8ca5f0e8 100644
--- a/sysdeps/s390/multiarch/wmemcmp.c
+++ b/sysdeps/s390/wmemcmp.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-wmemcmp.h>
+
+#if HAVE_WMEMCMP_IFUNC
 # include <wchar.h>
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc2 (__wmemcmp, wmemcmp)
+# if HAVE_WMEMCMP_C
+extern __typeof (wmemcmp) WMEMCMP_C attribute_hidden;
+# endif
+
+# if HAVE_WMEMCMP_Z13
+extern __typeof (wmemcmp) WMEMCMP_Z13 attribute_hidden;
+# endif
 
-#else
-# include <wcsmbs/wmemcmp.c>
-#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+s390_libc_ifunc_expr (wmemcmp, wmemcmp,
+		      (HAVE_WMEMCMP_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? WMEMCMP_Z13
+		      : WMEMCMP_DEFAULT
+		      )
+#endif