S390: Refactor memchr ifunc handling.

The ifunc handling for memchr 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.
Glibc internal calls will then also use the "newer" ifunc variant.

Note: The fallback s390-32/s390-64 ifunc variants with srst instruction
are now moved to the unified memchr-z900.S file which can be used for
31/64bit. The s390-32/s390-64 files multiarch/memchr.c and memchr.S
are deleted.

ChangeLog:

	* sysdeps/s390/multiarch/Makefile
	(sysdep_routines): Remove memchr variants.
	* sysdeps/s390/Makefile (sysdep_routines): Add memchr variants.
	* sysdeps/s390/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Refactor ifunc handling for memchr.
	* sysdeps/s390/multiarch/memchr-vx.S: Move to ...
	* sysdeps/s390/memchr-vx.S: ... here and adjust ifunc handling.
	* sysdeps/s390/multiarch/memchr.c: Move to ...
	* sysdeps/s390/memchr.c: ... here and adjust ifunc handling.
	* sysdeps/s390/ifunc-memchr.h: New file.
	* sysdeps/s390/s390-64/memchr.S: Move to ...
	* sysdeps/s390/memchr-z900.S: ... here and adjust to be usable
	for 31/64bit and ifunc handling.
	* sysdeps/s390/s390-32/multiarch/memchr.c: Delete file.
	* sysdeps/s390/s390-64/multiarch/memchr.c: Likewise.
	* sysdeps/s390/s390-32/memchr.S: Likewise.

1 files changed, 63 insertions, 0 deletions

diff --git a/sysdeps/s390/memchr-z900.S b/sysdeps/s390/memchr-z900.S
new file mode 100644
index 0000000..c016bc4
--- /dev/null
+++ b/sysdeps/s390/memchr-z900.S
@@ -0,0 +1,63 @@
+/* Search a character in a block of memory.  31/64 bit S/390 version.
+   Copyright (C) 2001-2018 Free Software Foundation, Inc.
+   Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
+   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/>.  */
+
+/* INPUT PARAMETERS
+     %r2 = address to memory area
+     %r3 = character to find
+     %r4 = number of bytes to search.  */
+
+#include <ifunc-memchr.h>
+#include "sysdep.h"
+#include "asm-syntax.h"
+
+#if HAVE_MEMCHR_Z900_G5
+# if defined __s390x__
+#  define SLGR	slgr
+#  define LGHI	lghi
+#  define NGR	ngr
+#  define LGR	lgr
+# else
+#  define SLGR	slr
+#  define LGHI	lhi
+#  define NGR	nr
+#  define LGR	lr
+# endif /* ! defined __s390x__  */
+
+	.text
+ENTRY(MEMCHR_Z900_G5)
+	LGHI  %r0,0xff
+	NGR   %r0,%r3
+	LGR   %r1,%r2
+	la    %r2,0(%r4,%r1)
+0:	srst  %r2,%r1
+	jo    0b
+	brc   13,1f
+	SLGR  %r2,%r2
+1:	br    %r14
+END(MEMCHR_Z900_G5)
+
+# if ! HAVE_MEMCHR_IFUNC
+strong_alias (MEMCHR_Z900_G5, __memchr)
+weak_alias (__memchr, memchr)
+# endif
+
+# if defined SHARED && IS_IN (libc)
+strong_alias (MEMCHR_Z900_G5, __GI_memchr)
+# endif
+#endif