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.

1 files changed, 182 insertions, 0 deletions

diff --git a/sysdeps/s390/wcsncmp-vx.S b/sysdeps/s390/wcsncmp-vx.S
new file mode 100644
index 0000000000..9bdd21acef
--- /dev/null
+++ b/sysdeps/s390/wcsncmp-vx.S
@@ -0,0 +1,182 @@
+/* Vector optimized 32/64 bit S/390 version of wcsncmp.
+   Copyright (C) 2015-2018 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/>.  */
+
+#include <ifunc-wcsncmp.h>
+#if HAVE_WCSNCMP_Z13
+
+# include "sysdep.h"
+# include "asm-syntax.h"
+
+	.text
+
+/* int wcsncmp (const wchar_t *s1, const wchar_t *s2, size_t n)
+   Compare at most n characters of two strings.
+
+   Register usage:
+   -r0=tmp
+   -r1=tmp
+   -r2=s1
+   -r3=s2
+   -r4=n
+   -r5=current_len
+   -v16=part of s1
+   -v17=part of s2
+   -v18=index of unequal
+*/
+ENTRY(WCSNCMP_Z13)
+	.machine "z13"
+	.machinemode "zarch_nohighgprs"
+
+# if !defined __s390x__
+	llgfr	%r4,%r4
+# endif /* !defined __s390x__ */
+
+	clgije	%r4,0,.Lend_equal /* Nothing to do if n == 0.  */
+
+	/* Check range of n and convert to byte-count.  */
+# ifdef __s390x__
+	tmhh	%r4,49152	/* Test bit 0 or 1 of maxlen.  */
+	lghi	%r1,-4		/* Max byte-count is 18446744073709551612.  */
+# else
+	tmlh	%r4,49152	/* Test bit 0 or 1 of maxlen.  */
+	llilf	%r1,4294967292	/* Max byte-count is 4294967292.  */
+# endif /* !__s390x__ */
+	sllg	%r4,%r4,2	/* Convert character-count to byte-count.  */
+	locgrne	%r4,%r1		/* Use max byte-count, if bit 0/1 was one.  */
+
+	/* Check first character without vector load.  */
+	lghi	%r5,4		/* current_len = 4 bytes.  */
+	/* Check s1/2[0].  */
+	lt	%r0,0(%r2)
+	l	%r1,0(%r3)
+	je	.Lend_cmp_one_char
+	crjne	%r0,%r1,.Lend_cmp_one_char
+
+.Lloop:
+	vlbb	%v17,0(%r5,%r3),6 /* Load s2 to block boundary.  */
+	vlbb	%v16,0(%r5,%r2),6 /* Load s1 to block boundary.  */
+	lcbb	%r0,0(%r5,%r2),6 /* Get loaded byte count of s1.  */
+	jo	.Llt16_1	/* Jump away if vector not fully loaded.  */
+	lcbb	%r1,0(%r5,%r3),6 /* Get loaded byte count of s2.  */
+	jo	.Llt16_2	/* Jump away if vector not fully loaded.  */
+	aghi	%r5,16		/* Both vectors are fully loaded.  */
+	vfenezfs %v18,%v16,%v17	/* Compare not equal with zero search.  */
+	clgrjhe	%r5,%r4,.Llastcmp /* If current_len >= n ->last compare.  */
+	jno	.Lfound
+
+	vlbb	%v17,0(%r5,%r3),6
+	vlbb	%v16,0(%r5,%r2),6
+	lcbb	%r0,0(%r5,%r2),6
+	jo	.Llt16_1
+	lcbb	%r1,0(%r5,%r3),6
+	jo	.Llt16_2
+	aghi	%r5,16
+	vfenezfs %v18,%v16,%v17
+	clgrjhe	%r5,%r4,.Llastcmp
+	jno	.Lfound
+
+	vlbb	%v17,0(%r5,%r3),6
+	vlbb	%v16,0(%r5,%r2),6
+	lcbb	%r0,0(%r5,%r2),6
+	jo	.Llt16_1
+	lcbb	%r1,0(%r5,%r3),6
+	jo	.Llt16_2
+	aghi	%r5,16
+	vfenezfs %v18,%v16,%v17
+	clgrjhe	%r5,%r4,.Llastcmp
+	jno	.Lfound
+
+	vlbb	%v17,0(%r5,%r3),6
+	vlbb	%v16,0(%r5,%r2),6
+	lcbb	%r0,0(%r5,%r2),6
+	jo	.Llt16_1
+	lcbb	%r1,0(%r5,%r3),6
+	jo	.Llt16_2
+	aghi	%r5,16
+	vfenezfs %v18,%v16,%v17
+	clgrjhe	%r5,%r4,.Llastcmp
+	jno	.Lfound
+
+	j	.Lloop
+
+.Llt16_1:
+	lcbb	%r1,0(%r5,%r3),6 /* Get loaded byte count of s2.  */
+.Llt16_2:
+	clr	%r0,%r1		/* Compare logical.  */
+	locrh	%r0,%r1		/* Compute minimum of bytes loaded.  */
+	nill	%r0,65532	/* Align bytes loaded to full characters.  */
+	jz	.Lcmp_one_char	/* Jump away if no full char is available.  */
+.Llt_cmp:
+	algfr	%r5,%r0		/* Add smallest loaded bytes to current_len.  */
+	vfenezfs %v18,%v16,%v17	/* Compare not equal with zero search.  */
+	clgrj	%r5,%r4,10,.Llastcmp /* If current_len >= n -> last compare  */
+	vlgvb	%r1,%v18,7	/* Get not equal index or 16 if all equal.  */
+	clrjl	%r1,%r0,.Lfound /* Jump away if miscompare is within
+				   loaded bytes; (index < loaded-bytes) */
+	j	.Lloop
+
+.Lcmp_one_char:
+	/* At least one of both strings is not 4-byte aligned
+	   and there is no full character before next block-boundary.
+	   Compare one character to get over the boundary and
+	   proceed with normal loop!  */
+	vlef	%v16,0(%r5,%r2),0 /* Load one character.  */
+	lghi	%r0,4		/* Loaded byte count is 4.  */
+	vlef	%v17,0(%r5,%r3),0
+	j	.Llt_cmp	/* Proceed with comparision.  */
+
+.Llastcmp:
+	/* Use comparision result only if located within first n characters.
+	   %r0: loaded byte count in vreg;
+	   %r5: current_len;
+	   %r4: n;
+	   (current_len - n): [0...16[
+	   First ignored match index: loaded bytes - (current_len-n): ]0...16]
+	*/
+	slgr	%r5,%r4		/* %r5 = current_len - n.  */
+	slr	%r0,%r5		/* %r0 = first ignored match index.  */
+	vlgvb	%r4,%v18,7	/* Get not equal index or 16 if all equal.  */
+	clrjl	%r4,%r0,.Lfound2 /* Jump away if miscompare is within
+				     loaded bytes and below n bytes.  */
+.Lend_equal:
+	lghi	%r2,0
+	br	%r14
+
+.Lfound:
+	/* Difference or end of string.  */
+	/* vfenezf found an unequal element or zero.
+	   This instruction compares unsigned words, but wchar_t is signed.
+	   Thus we have to compare the found element again.  */
+	vlgvb	%r4,%v18,7	/* Extract not equal byte-index.  */
+.Lfound2:
+	srl	%r4,2		/* And convert it to character-index.  */
+	vlgvf	%r0,%v16,0(%r4)	/* Load character-values.  */
+	vlgvf	%r1,%v17,0(%r4)
+.Lend_cmp_one_char:
+	cr	%r0,%r1
+	je	.Lend_equal
+	lghi	%r2,1
+	lghi	%r1,-1
+	locgrl	%r2,%r1
+	br	%r14
+END(WCSNCMP_Z13)
+
+# if ! HAVE_WCSNCMP_IFUNC
+strong_alias (WCSNCMP_Z13, wcsncmp)
+# endif
+#endif