[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/include/asm/string.h b/arch/s390/include/asm/string.h
index adf0791..cd0241d 100644
--- a/arch/s390/include/asm/string.h
+++ b/arch/s390/include/asm/string.h
@@ -100,6 +100,7 @@
static inline char *strcpy(char *dst, const char *src)
{
+#if __GNUC__ < 4
register int r0 asm("0") = 0;
char *ret = dst;
@@ -109,10 +110,14 @@
: "+&a" (dst), "+&a" (src) : "d" (r0)
: "cc", "memory");
return ret;
+#else
+ return __builtin_strcpy(dst, src);
+#endif
}
static inline size_t strlen(const char *s)
{
+#if __GNUC__ < 4
register unsigned long r0 asm("0") = 0;
const char *tmp = s;
@@ -121,6 +126,9 @@
" jo 0b"
: "+d" (r0), "+a" (tmp) : : "cc");
return r0 - (unsigned long) s;
+#else
+ return __builtin_strlen(s);
+#endif
}
static inline size_t strnlen(const char * s, size_t n)