[S390] use compiler builtin versions of strlen/strcpy/strcat
Use builtin variants if gcc 4 or newer is used to compile the kernel.
Generates better code than the asm variants.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/lib/string.c b/arch/s390/lib/string.c
index ae5cf5d..4143b7c 100644
--- a/arch/s390/lib/string.c
+++ b/arch/s390/lib/string.c
@@ -44,7 +44,11 @@
*/
size_t strlen(const char *s)
{
+#if __GNUC__ < 4
return __strend(s) - s;
+#else
+ return __builtin_strlen(s);
+#endif
}
EXPORT_SYMBOL(strlen);
@@ -70,6 +74,7 @@
*/
char *strcpy(char *dest, const char *src)
{
+#if __GNUC__ < 4
register int r0 asm("0") = 0;
char *ret = dest;
@@ -78,6 +83,9 @@
: "+&a" (dest), "+&a" (src) : "d" (r0)
: "cc", "memory" );
return ret;
+#else
+ return __builtin_strcpy(dest, src);
+#endif
}
EXPORT_SYMBOL(strcpy);