From d3496c9f4f27d3009b71be87f6108b4fed7314bd Mon Sep 17 00:00:00 2001 From: Wilco Dijkstra Date: Fri, 25 Mar 2016 16:44:26 -0300 Subject: Improve generic strcspn performance Improve strcspn performance using a much faster algorithm. It is kept simple so it works well on most targets. It is generally at least 10 times faster than the existing implementation on bench-strcspn on a few AArch64 implementations, and for some tests 100 times as fast (repeatedly calling strchr on a small string is extremely slow...). In fact the string/bits/string2.h inlines make no longer sense, as GCC already uses strlen if reject is an empty string, strchrnul is 5 times as fast as __strcspn_c1, while __strcspn_c2 and __strcspn_c3 are slower than the strcspn main loop for large strings (though reject length 2-4 could be special cased in the future to gain even more performance). Tested on x86_64, i686, and aarch64. * string/Version (libc): Add GLIBC_2.24. * string/strcspn.c (strcspn): Rewrite function. * string/bits/string2.h (strcspn): Use __builtin_strcspn. (__strcspn_c1): Remove inline function. (__strcspn_c2): Likewise. (__strcspn_c3): Likewise. * string/string-inline.c [SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strcspn_c1): Add compatibility symbol. [SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strcspn_c2): Likewise. [SHLIB_COMPAT(libc, GLIBC_2_1_1, GLIBC_2_24)] (__strcspn_c3): Likewise. * sysdeps/i386/string-inlines.c: Include generic string-inlines.c. --- string/bits/string2.h | 73 +++------------------------------------------------ 1 file changed, 3 insertions(+), 70 deletions(-) (limited to 'string/bits/string2.h') diff --git a/string/bits/string2.h b/string/bits/string2.h index 8200ef173d..a8df0db14a 100644 --- a/string/bits/string2.h +++ b/string/bits/string2.h @@ -905,77 +905,10 @@ __stpcpy_small (char *__dest, /* Return the length of the initial segment of S which consists entirely of characters not in REJECT. */ -#if !defined _HAVE_STRING_ARCH_strcspn || defined _FORCE_INLINES -# ifndef _HAVE_STRING_ARCH_strcspn -# if __GNUC_PREREQ (3, 2) -# define strcspn(s, reject) \ - __extension__ \ - ({ char __r0, __r1, __r2; \ - (__builtin_constant_p (reject) && __string2_1bptr_p (reject) \ - ? ((__builtin_constant_p (s) && __string2_1bptr_p (s)) \ - ? __builtin_strcspn (s, reject) \ - : ((__r0 = ((const char *) (reject))[0], __r0 == '\0') \ - ? strlen (s) \ - : ((__r1 = ((const char *) (reject))[1], __r1 == '\0') \ - ? __strcspn_c1 (s, __r0) \ - : ((__r2 = ((const char *) (reject))[2], __r2 == '\0') \ - ? __strcspn_c2 (s, __r0, __r1) \ - : (((const char *) (reject))[3] == '\0' \ - ? __strcspn_c3 (s, __r0, __r1, __r2) \ - : __builtin_strcspn (s, reject)))))) \ - : __builtin_strcspn (s, reject)); }) -# else -# define strcspn(s, reject) \ - __extension__ \ - ({ char __r0, __r1, __r2; \ - (__builtin_constant_p (reject) && __string2_1bptr_p (reject) \ - ? ((__r0 = ((const char *) (reject))[0], __r0 == '\0') \ - ? strlen (s) \ - : ((__r1 = ((const char *) (reject))[1], __r1 == '\0') \ - ? __strcspn_c1 (s, __r0) \ - : ((__r2 = ((const char *) (reject))[2], __r2 == '\0') \ - ? __strcspn_c2 (s, __r0, __r1) \ - : (((const char *) (reject))[3] == '\0' \ - ? __strcspn_c3 (s, __r0, __r1, __r2) \ - : strcspn (s, reject))))) \ - : strcspn (s, reject)); }) -# endif +#ifndef _HAVE_STRING_ARCH_strcspn +# if __GNUC_PREREQ (3, 2) +# define strcspn(s, reject) __builtin_strcspn (s, reject) # endif - -__STRING_INLINE size_t __strcspn_c1 (const char *__s, int __reject); -__STRING_INLINE size_t -__strcspn_c1 (const char *__s, int __reject) -{ - size_t __result = 0; - while (__s[__result] != '\0' && __s[__result] != __reject) - ++__result; - return __result; -} - -__STRING_INLINE size_t __strcspn_c2 (const char *__s, int __reject1, - int __reject2); -__STRING_INLINE size_t -__strcspn_c2 (const char *__s, int __reject1, int __reject2) -{ - size_t __result = 0; - while (__s[__result] != '\0' && __s[__result] != __reject1 - && __s[__result] != __reject2) - ++__result; - return __result; -} - -__STRING_INLINE size_t __strcspn_c3 (const char *__s, int __reject1, - int __reject2, int __reject3); -__STRING_INLINE size_t -__strcspn_c3 (const char *__s, int __reject1, int __reject2, - int __reject3) -{ - size_t __result = 0; - while (__s[__result] != '\0' && __s[__result] != __reject1 - && __s[__result] != __reject2 && __s[__result] != __reject3) - ++__result; - return __result; -} #endif -- cgit 1.4.1