From 838951c97edc05cb2a25948ee542415b55b8f605 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Mon, 22 Oct 2012 15:17:09 -0400 Subject: [PATCH] simplify logic in stpcpy; avoid copying first aligned byte twice gcc seems to be generating identical or near-identical code for both versions, but the newer code is more expressive of what it's doing. --- src/string/stpcpy.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/string/stpcpy.c b/src/string/stpcpy.c index da96f215..feb9eb81 100644 --- a/src/string/stpcpy.c +++ b/src/string/stpcpy.c @@ -4,7 +4,7 @@ #include #include "libc.h" -#define ALIGN (sizeof(size_t)-1) +#define ALIGN (sizeof(size_t)) #define ONES ((size_t)-1/UCHAR_MAX) #define HIGHS (ONES * (UCHAR_MAX/2+1)) #define HASZERO(x) ((x)-ONES & ~(x) & HIGHS) @@ -14,9 +14,9 @@ char *__stpcpy(char *restrict d, const char *restrict s) size_t *wd; const size_t *ws; - if (((uintptr_t)s & ALIGN) == ((uintptr_t)d & ALIGN)) { - for (; (*d=*s) && ((uintptr_t)s & ALIGN); s++, d++); - if (!*s) return d; + if ((uintptr_t)s % ALIGN == (uintptr_t)d % ALIGN) { + for (; (uintptr_t)s % ALIGN; s++, d++) + if (!(*d=*s)) return d; wd=(void *)d; ws=(const void *)s; for (; !HASZERO(*ws); *wd++ = *ws++); d=(void *)wd; s=(const void *)ws; -- 2.20.1