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S390: Optimize strncmp and wcsncmp.
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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.
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Stefan Liebler authored and Andreas Krebbel committed Aug 26, 2015
1 parent 63724a6 commit cee82e7
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Showing 13 changed files with 558 additions and 29 deletions.
17 changes: 17 additions & 0 deletions ChangeLog
Original file line number Diff line number Diff line change
@@ -1,3 +1,20 @@
2015-08-26 Stefan Liebler <stli@linux.vnet.ibm.com>

* 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.

2015-08-26 Stefan Liebler <stli@linux.vnet.ibm.com>

* sysdeps/s390/multiarch/strcmp-vx.S: New File.
Expand Down
2 changes: 1 addition & 1 deletion benchtests/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@ string-bench := bcopy bzero memccpy memchr memcmp memcpy memmem memmove \
strspn strstr strcpy_chk stpcpy_chk memrchr strsep strtok \
strcoll
wcsmbs-bench := wcslen wcsnlen wcscpy wcpcpy wcsncpy wcpncpy wcscat wcsncat \
wcscmp
wcscmp wcsncmp
string-bench-all := $(string-bench) ${wcsmbs-bench}

# We have to generate locales
Expand Down
110 changes: 85 additions & 25 deletions benchtests/bench-strncmp.c
Original file line number Diff line number Diff line change
Expand Up @@ -17,17 +17,68 @@
<http://www.gnu.org/licenses/>. */

#define TEST_MAIN
#define TEST_NAME "strncmp"
#ifdef WIDE
# define TEST_NAME "wcsncmp"
#else
# define TEST_NAME "strncmp"
#endif /* !WIDE */
#include "bench-string.h"

typedef int (*proto_t) (const char *, const char *, size_t);
int simple_strncmp (const char *, const char *, size_t);
int stupid_strncmp (const char *, const char *, size_t);
#ifdef WIDE
# include <wchar.h>

IMPL (stupid_strncmp, 0)
IMPL (simple_strncmp, 0)
IMPL (strncmp, 1)
# define L(str) L##str
# define STRNCMP wcsncmp
# define SIMPLE_STRNCMP simple_wcsncmp
# define STUPID_STRNCMP stupid_wcsncmp
# define CHAR wchar_t
# define CHARBYTES 4

/* Wcsncmp uses signed semantics for comparison, not unsigned.
Avoid using substraction since possible overflow. */
int
simple_wcsncmp (const CHAR *s1, const CHAR *s2, size_t n)
{
wchar_t c1, c2;

while (n--)
{
c1 = *s1++;
c2 = *s2++;
if (c1 == L ('\0') || c1 != c2)
return c1 > c2 ? 1 : (c1 < c2 ? -1 : 0);
}
return 0;
}

int
stupid_wcsncmp (const CHAR *s1, const CHAR *s2, size_t n)
{
wchar_t c1, c2;
size_t ns1 = wcsnlen (s1, n) + 1, ns2 = wcsnlen (s2, n) + 1;

n = ns1 < n ? ns1 : n;
n = ns2 < n ? ns2 : n;

while (n--)
{
c1 = *s1++;
c2 = *s2++;
if (c1 != c2)
return c1 > c2 ? 1 : -1;
}
return 0;
}

#else
# define L(str) str
# define STRNCMP strncmp
# define SIMPLE_STRNCMP simple_strncmp
# define STUPID_STRNCMP stupid_strncmp
# define CHAR char
# define CHARBYTES 1

/* Strncmp uses unsigned semantics for comparison. */
int
simple_strncmp (const char *s1, const char *s2, size_t n)
{
Expand All @@ -46,12 +97,21 @@ stupid_strncmp (const char *s1, const char *s2, size_t n)

n = ns1 < n ? ns1 : n;
n = ns2 < n ? ns2 : n;
while (n-- && (ret = *(unsigned char *) s1++ - * (unsigned char *) s2++) == 0);
while (n-- && (ret = *(unsigned char *) s1++ - *(unsigned char *) s2++) == 0);
return ret;
}

#endif /* !WIDE */

typedef int (*proto_t) (const CHAR *, const CHAR *, size_t);

IMPL (STUPID_STRNCMP, 0)
IMPL (SIMPLE_STRNCMP, 0)
IMPL (STRNCMP, 1)


static void
do_one_test (impl_t *impl, const char *s1, const char *s2, size_t n,
do_one_test (impl_t *impl, const CHAR *s1, const CHAR *s2, size_t n,
int exp_result)
{
size_t i, iters = INNER_LOOP_ITERS;
Expand All @@ -74,12 +134,12 @@ do_test_limit (size_t align1, size_t align2, size_t len, size_t n, int max_char,
int exp_result)
{
size_t i, align_n;
char *s1, *s2;
CHAR *s1, *s2;

if (n == 0)
{
s1 = (char*)(buf1 + page_size);
s2 = (char*)(buf2 + page_size);
s1 = (CHAR *) (buf1 + page_size);
s2 = (CHAR *) (buf2 + page_size);
printf ("Length %4zd/%4zd:", len, n);

FOR_EACH_IMPL (impl, 0)
Expand All @@ -92,16 +152,16 @@ do_test_limit (size_t align1, size_t align2, size_t len, size_t n, int max_char,

align1 &= 15;
align2 &= 15;
align_n = (page_size - n) & 15;
align_n = (page_size - n * CHARBYTES) & 15;

s1 = (char*)(buf1 + page_size - n);
s2 = (char*)(buf2 + page_size - n);
s1 = (CHAR *) (buf1 + page_size - n * CHARBYTES);
s2 = (CHAR *) (buf2 + page_size - n * CHARBYTES);

if (align1 < align_n)
s1 -= (align_n - align1);
s1 = (CHAR *) ((char *) s1 - (align_n - align1));

if (align2 < align_n)
s2 -= (align_n - align2);
s2 = (CHAR *) ((char *) s2 - (align_n - align2));

for (i = 0; i < n; i++)
s1[i] = s2[i] = 1 + 23 * i % max_char;
Expand Down Expand Up @@ -129,24 +189,24 @@ do_test (size_t align1, size_t align2, size_t len, size_t n, int max_char,
int exp_result)
{
size_t i;
char *s1, *s2;
CHAR *s1, *s2;

if (n == 0)
return;

align1 &= 7;
if (align1 + n + 1 >= page_size)
align1 &= 63;
if (align1 + (n + 1) * CHARBYTES >= page_size)
return;

align2 &= 7;
if (align2 + n + 1 >= page_size)
if (align2 + (n + 1) * CHARBYTES >= page_size)
return;

s1 = (char*)(buf1 + align1);
s2 = (char*)(buf2 + align2);
s1 = (CHAR *) (buf1 + align1);
s2 = (CHAR *) (buf2 + align2);

for (i = 0; i < n; i++)
s1[i] = s2[i] = 1 + 23 * i % max_char;
s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % max_char;

s1[n] = 24 + exp_result;
s2[n] = 23;
Expand All @@ -162,7 +222,7 @@ do_test (size_t align1, size_t align2, size_t len, size_t n, int max_char,
printf ("Length %4zd/%4zd, alignment %2zd/%2zd:", len, n, align1, align2);

FOR_EACH_IMPL (impl, 0)
do_one_test (impl, (char*)s1, (char*)s2, n, exp_result);
do_one_test (impl, s1, s2, n, exp_result);

putchar ('\n');
}
Expand Down
20 changes: 20 additions & 0 deletions benchtests/bench-wcsncmp.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
/* Measure wcsncmp functions.
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/>. */

#define WIDE 1
#include "bench-strncmp.c"
6 changes: 4 additions & 2 deletions sysdeps/s390/multiarch/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,8 @@ sysdep_routines += strlen strlen-vx strlen-c \
stpncpy stpncpy-vx stpncpy-c \
strcat strcat-vx strcat-c \
strncat strncat-vx strncat-c \
strcmp strcmp-vx
strcmp strcmp-vx \
strncmp strncmp-vx strncmp-c
endif

ifeq ($(subdir),wcsmbs)
Expand All @@ -19,5 +20,6 @@ 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
3 changes: 3 additions & 0 deletions sysdeps/s390/multiarch/ifunc-impl-list.c
Original file line number Diff line number Diff line change
Expand Up @@ -106,6 +106,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
IFUNC_VX_IMPL (strcmp);
IFUNC_VX_IMPL (wcscmp);

IFUNC_VX_IMPL (strncmp);
IFUNC_VX_IMPL (wcsncmp);

#endif /* HAVE_S390_VX_ASM_SUPPORT */

return i;
Expand Down
28 changes: 28 additions & 0 deletions sysdeps/s390/multiarch/strncmp-c.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
/* Default strncmp implementation for S/390.
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)
# define STRNCMP __strncmp_c
# ifdef SHARED
# undef libc_hidden_builtin_def
# define libc_hidden_builtin_def(name) \
__hidden_ver1 (__strncmp_c, __GI_strncmp, __strncmp_c);
# endif /* SHARED */

# include <string/strncmp.c>
#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
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