From 6e46de42fe1695818a410a7b86d26be8b1527524 Mon Sep 17 00:00:00 2001 From: Wilco Dijkstra Date: Fri, 24 Oct 2014 16:08:42 +0000 Subject: [PATCH] This patch improves strcat performance by using strlen and strcpy. Strlen has a fast C implementation, so this improves performance even on targets which don't have an optimized strlen and strcpy - it is 25% faster in bench-strcat. On targets which don't provide an optimized strcat but which do have an optimized strlen and strcpy, performance gain is > 2x. --- ChangeLog | 4 ++++ string/strcat.c | 21 +-------------------- 2 files changed, 5 insertions(+), 20 deletions(-) diff --git a/ChangeLog b/ChangeLog index 98548cbaf9f..f73c55e5d45 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,7 @@ +2014-10-24 Wilco Dijkstra + + * string/strcat.c (strcat): Improve performance by using strlen/strcpy. + 2014-10-24 Wilco Dijkstra * sysdeps/aarch64/fpu/fgetexcptflg.c (fegetexceptflag): diff --git a/string/strcat.c b/string/strcat.c index 2cbe8b32dac..983d1157070 100644 --- a/string/strcat.c +++ b/string/strcat.c @@ -23,26 +23,7 @@ char * strcat (char *dest, const char *src) { - char *s1 = dest; - const char *s2 = src; - char c; - - /* Find the end of the string. */ - do - c = *s1++; - while (c != '\0'); - - /* Make S1 point before the next character, so we can increment - it while memory is read (wins on pipelined cpus). */ - s1 -= 2; - - do - { - c = *s2++; - *++s1 = c; - } - while (c != '\0'); - + strcpy (dest + strlen (dest), src); return dest; } libc_hidden_builtin_def (strcat) -- 2.39.5