1#include <string.h>
 2#include <stdint.h>
 3#include <limits.h>
 4
 5#define ALIGN (sizeof(size_t))
 6#define ONES ((size_t)-1/UCHAR_MAX)
 7#define HIGHS (ONES * (UCHAR_MAX/2+1))
 8#define HASZERO(x) ((x)-ONES & ~(x) & HIGHS)
 9
10char *__stpcpy(char *restrict d, const char *restrict s)
11{
12#ifdef __GNUC__
13	typedef size_t __attribute__((__may_alias__)) word;
14	word *wd;
15	const word *ws;
16	if ((uintptr_t)s % ALIGN == (uintptr_t)d % ALIGN) {
17		for (; (uintptr_t)s % ALIGN; s++, d++)
18			if (!(*d=*s)) return d;
19		wd=(void *)d; ws=(const void *)s;
20		for (; !HASZERO(*ws); *wd++ = *ws++);
21		d=(void *)wd; s=(const void *)ws;
22	}
23#endif
24	for (; (*d=*s); s++, d++);
25
26	return d;
27}
28
29weak_alias(__stpcpy, stpcpy);