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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2016-03-26 19:09:07 +0000 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2016-04-01 10:44:44 -0300 |
commit | 91f3b75f47c9eca3299098c3dcc2f5d9dad320b1 (patch) | |
tree | f00e3a58386999ac44a322211ff74cffcb37df99 /string/bits/string2.h | |
parent | d3496c9f4f27d3009b71be87f6108b4fed7314bd (diff) | |
download | glibc-91f3b75f47c9eca3299098c3dcc2f5d9dad320b1.zip glibc-91f3b75f47c9eca3299098c3dcc2f5d9dad320b1.tar.gz glibc-91f3b75f47c9eca3299098c3dcc2f5d9dad320b1.tar.bz2 |
Improve generic strspn performance
As for strcspn, this patch improves strspn performance using a much
faster algorithm. It first constructs a 256-entry table based on
the accept string and then uses it as a lookup table for the
input string. As for strcspn optimization, it is generally at least
10 times faster than the existing implementation on bench-strspn
on a few AArch64 implementations.
Also the string/bits/string2.h inlines make no longer sense, as current
implementation will already implement most of the optimizations.
Tested on x86_64, i686, and aarch64.
* string/strspn.c (strcspn): Rewrite function.
* string/bits/string2.h (strspn): Use __builtin_strcspn.
(__strspn_c1): Remove inline function.
(__strspn_c2): Likewise.
(__strspn_c3): Likewise.
* string/string-inlines.c
[SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strspn_c1): Add
compatibility symbol.
[SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strspn_c2):
Likewise.
[SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strspn_c3):
Likewise.
Diffstat (limited to 'string/bits/string2.h')
-rw-r--r-- | string/bits/string2.h | 74 |
1 files changed, 3 insertions, 71 deletions
diff --git a/string/bits/string2.h b/string/bits/string2.h index a8df0db..75a66a1 100644 --- a/string/bits/string2.h +++ b/string/bits/string2.h @@ -914,78 +914,10 @@ __stpcpy_small (char *__dest, /* Return the length of the initial segment of S which consists entirely of characters in ACCEPT. */ -#if !defined _HAVE_STRING_ARCH_strspn || defined _FORCE_INLINES -# ifndef _HAVE_STRING_ARCH_strspn -# if __GNUC_PREREQ (3, 2) -# define strspn(s, accept) \ - __extension__ \ - ({ char __a0, __a1, __a2; \ - (__builtin_constant_p (accept) && __string2_1bptr_p (accept) \ - ? ((__builtin_constant_p (s) && __string2_1bptr_p (s)) \ - ? __builtin_strspn (s, accept) \ - : ((__a0 = ((const char *) (accept))[0], __a0 == '\0') \ - ? ((void) (s), (size_t) 0) \ - : ((__a1 = ((const char *) (accept))[1], __a1 == '\0') \ - ? __strspn_c1 (s, __a0) \ - : ((__a2 = ((const char *) (accept))[2], __a2 == '\0') \ - ? __strspn_c2 (s, __a0, __a1) \ - : (((const char *) (accept))[3] == '\0' \ - ? __strspn_c3 (s, __a0, __a1, __a2) \ - : __builtin_strspn (s, accept)))))) \ - : __builtin_strspn (s, accept)); }) -# else -# define strspn(s, accept) \ - __extension__ \ - ({ char __a0, __a1, __a2; \ - (__builtin_constant_p (accept) && __string2_1bptr_p (accept) \ - ? ((__a0 = ((const char *) (accept))[0], __a0 == '\0') \ - ? ((void) (s), (size_t) 0) \ - : ((__a1 = ((const char *) (accept))[1], __a1 == '\0') \ - ? __strspn_c1 (s, __a0) \ - : ((__a2 = ((const char *) (accept))[2], __a2 == '\0') \ - ? __strspn_c2 (s, __a0, __a1) \ - : (((const char *) (accept))[3] == '\0' \ - ? __strspn_c3 (s, __a0, __a1, __a2) \ - : strspn (s, accept))))) \ - : strspn (s, accept)); }) -# endif +#ifndef _HAVE_STRING_ARCH_strspn +# if __GNUC_PREREQ (3, 2) +# define strspn(s, accept) __builtin_strspn (s, accept) # endif - -__STRING_INLINE size_t __strspn_c1 (const char *__s, int __accept); -__STRING_INLINE size_t -__strspn_c1 (const char *__s, int __accept) -{ - size_t __result = 0; - /* Please note that __accept never can be '\0'. */ - while (__s[__result] == __accept) - ++__result; - return __result; -} - -__STRING_INLINE size_t __strspn_c2 (const char *__s, int __accept1, - int __accept2); -__STRING_INLINE size_t -__strspn_c2 (const char *__s, int __accept1, int __accept2) -{ - size_t __result = 0; - /* Please note that __accept1 and __accept2 never can be '\0'. */ - while (__s[__result] == __accept1 || __s[__result] == __accept2) - ++__result; - return __result; -} - -__STRING_INLINE size_t __strspn_c3 (const char *__s, int __accept1, - int __accept2, int __accept3); -__STRING_INLINE size_t -__strspn_c3 (const char *__s, int __accept1, int __accept2, int __accept3) -{ - size_t __result = 0; - /* Please note that __accept1 to __accept3 never can be '\0'. */ - while (__s[__result] == __accept1 || __s[__result] == __accept2 - || __s[__result] == __accept3) - ++__result; - return __result; -} #endif |