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/string-inlines.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'string/string-inlines.c') diff --git a/string/string-inlines.c b/string/string-inlines.c index 16db3ea308..83bdd6c185 100644 --- a/string/string-inlines.c +++ b/string/string-inlines.c @@ -32,3 +32,43 @@ #undef __NO_INLINE__ #include #include + +#include "shlib-compat.h" + +#if SHLIB_COMPAT (libc, GLIBC_2_1_1, GLIBC_2_24) +/* The inline functions are not used from GLIBC 2.24 and forward, however + they are required to provide the symbols through string-inlines.c + (if inlining is not possible for compatibility reasons). */ +size_t +__old_strcspn_c1 (const char *__s, int __reject) +{ + size_t __result = 0; + while (__s[__result] != '\0' && __s[__result] != __reject) + ++__result; + return __result; +} +compat_symbol (libc, __old_strcspn_c1, __strcspn_c1, GLIBC_2_1_1); + +size_t +__old_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; +} +compat_symbol (libc, __old_strcspn_c2, __strcspn_c2, GLIBC_2_1_1); + +size_t +__old_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; +} +compat_symbol (libc, __old_strcspn_c3, __strcspn_c3, GLIBC_2_1_1); +#endif -- cgit v1.2.3