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This patch improves strcat performance by using strlen and strcpy. Strlen has a fast C

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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.
This commit is contained in:
Wilco Dijkstra
2014-10-24 16:08:42 +00:00
parent 6a9ad2faee
commit 6e46de42fe
2 changed files with 5 additions and 20 deletions
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ChangeLog
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@ -1,3 +1,7 @@
2014-10-24 Wilco Dijkstra <wdijkstr@arm.com>
* string/strcat.c (strcat): Improve performance by using strlen/strcpy.
2014-10-24 Wilco Dijkstra <wdijkstr@arm.com> 2014-10-24 Wilco Dijkstra <wdijkstr@arm.com>
* sysdeps/aarch64/fpu/fgetexcptflg.c (fegetexceptflag): * sysdeps/aarch64/fpu/fgetexcptflg.c (fegetexceptflag):

21
string/strcat.c
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@ -23,26 +23,7 @@
char * char *
strcat (char *dest, const char *src) strcat (char *dest, const char *src)
{ {
char *s1 = dest; strcpy (dest + strlen (dest), src);
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');
return dest; return dest;
} }
libc_hidden_builtin_def (strcat) libc_hidden_builtin_def (strcat)