S390: Optimize strncmp and wcsncmp.

This patch provides optimized versions of strncmp and wcsncmp with the z13
vector instructions.

ChangeLog:

	* sysdeps/s390/multiarch/strncmp-c.c: New File.
	* sysdeps/s390/multiarch/strncmp-vx.S: Likewise.
	* sysdeps/s390/multiarch/strncmp.c: Likewise.
	* sysdeps/s390/multiarch/wcsncmp-c.c: Likewise.
	* sysdeps/s390/multiarch/wcsncmp-vx.S: Likewise.
	* sysdeps/s390/multiarch/wcsncmp.c: Likewise.
	* sysdeps/s390/multiarch/Makefile (sysdep_routines): Add strncmp and
	wcsncmp functions.
	* sysdeps/s390/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Add ifunc test for strncmp, wcsncmp.
	* wcsmbs/wcsncmp.c (WCSNCMP): Define and use macro.
	* benchtests/bench-strncmp.c: Add wcsncmp support.
	* benchtests/bench-wcsncmp.c: New File.
	* benchtests/Makefile (wcsmbs-bench): Add wcsncmp.

1 files changed, 137 insertions, 0 deletions

diff --git a/sysdeps/s390/multiarch/strncmp-vx.S b/sysdeps/s390/multiarch/strncmp-vx.S
new file mode 100644
index 0000000000..ad010798d9
--- /dev/null
+++ b/sysdeps/s390/multiarch/strncmp-vx.S
@@ -0,0 +1,137 @@
+/* Vector optimized 32/64 bit S/390 version of strncmp.
+   Copyright (C) 2015 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 HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
+
+# include "sysdep.h"
+# include "asm-syntax.h"
+
+	.text
+
+/* int strncmp (const char *s1, const char *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(__strncmp_vx)
+	.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,  */
+	lghi	%r5,0		/* current_len = 0.  */
+
+.Lloop:
+	vlbb	%v16,0(%r5,%r2),6 /* Load s1 to block boundary.  */
+	vlbb	%v17,0(%r5,%r3),6 /* Load s2 to block boundary.  */
+	lcbb	%r0,0(%r5,%r2),6 /* Get loaded byte count of s1.  */
+	jo	.Llt16_1	/* Jump away if vr is not fully loaded.  */
+	lcbb	%r1,0(%r5,%r3),6 /* Get loaded byte count of s2.  */
+	jo	.Llt16_2	/* Jump away if vr is not fully loaded.  */
+	aghi	%r5,16		/* Both vrs are fully loaded.  */
+	clgrjhe	%r5,%r4,.Llastcmp /* If current_len >= n ->last compare.  */
+	vfenezbs %v18,%v16,%v17	/* Compare not equal with zero search.  */
+	jno	.Lfound
+
+	vlbb	%v16,0(%r5,%r2),6
+	vlbb	%v17,0(%r5,%r3),6
+	lcbb	%r0,0(%r5,%r2),6
+	jo	.Llt16_1
+	lcbb	%r1,0(%r5,%r3),6
+	jo	.Llt16_2
+	aghi	%r5,16
+	clgrjhe	%r5,%r4,.Llastcmp
+	vfenezbs %v18,%v16,%v17
+	jno	.Lfound
+
+	vlbb	%v16,0(%r5,%r2),6
+	vlbb	%v17,0(%r5,%r3),6
+	lcbb	%r0,0(%r5,%r2),6
+	jo	.Llt16_1
+	lcbb	%r1,0(%r5,%r3),6
+	jo	.Llt16_2
+	aghi	%r5,16
+	clgrjhe	%r5,%r4,.Llastcmp
+	vfenezbs %v18,%v16,%v17
+	jno	.Lfound
+
+	vlbb	%v16,0(%r5,%r2),6
+	vlbb	%v17,0(%r5,%r3),6
+	lcbb	%r0,0(%r5,%r2),6
+	jo	.Llt16_1
+	lcbb	%r1,0(%r5,%r3),6
+	jo	.Llt16_2
+	aghi	%r5,16
+	clgrjhe	%r5,%r4,.Llastcmp
+	vfenezbs %v18,%v16,%v17
+	jno	.Lfound
+	j	.Lloop
+
+.Llt16_1:
+	lcbb	%r1,0(%r5,%r3),6 /* Get loaded byte count ofs2.  */
+.Llt16_2:
+	clr	%r0,%r1		/* Compare logical.  */
+	locrh	%r0,%r1		/* Compute minimum of bytes loaded.  */
+	algfr	%r5,%r0		/* Add smallest loaded bytes to current_len.  */
+	clgrj	%r5,%r4,10,.Llastcmp /* If current_len >= n ->last compare.  */
+	vfenezbs %v18,%v16,%v17	/* Compare not equal with zero search.  */
+	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
+
+.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.  */
+	vfenezbs %v18,%v16,%v17	/* Compare not equal with zero search.  */
+	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 and below n bytes.  */
+	j	.Lend_equal	/* Miscompare after n-bytes -> end equal.  */
+
+.Lfound:
+	/* Difference or end of string.  */
+	je	.Lend_equal
+	lghi	%r2,1
+	lghi	%r1,-1
+	locgrl	%r2,%r1
+	br	%r14
+.Lend_equal:
+	lghi	%r2,0
+	br	%r14
+END(__strncmp_vx)
+#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */