diff options
Diffstat (limited to 'string/bits/string2.h')
| -rw-r--r-- | string/bits/string2.h | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/string/bits/string2.h b/string/bits/string2.h index 665a711e7d..ba84da2346 100644 --- a/string/bits/string2.h +++ b/string/bits/string2.h @@ -94,9 +94,10 @@ __STRING2_COPY_TYPE (8); ((size_t)(const void *)((__x) + 1) - (size_t)(const void *)(__x) == 1) /* Set N bytes of S to C. */ -#if !defined _HAVE_STRING_ARCH_memset && ! __GNUC_PREREQ (3, 0) -# if _STRING_ARCH_unaligned -# define memset(s, c, n) \ +#if !defined _HAVE_STRING_ARCH_memset +# if !__GNUC_PREREQ (3, 0) +# if _STRING_ARCH_unaligned +# define memset(s, c, n) \ (__extension__ (__builtin_constant_p (n) && (n) <= 16 \ ? ((n) == 1 \ ? __memset_1 (s, c) \ @@ -105,10 +106,10 @@ __STRING2_COPY_TYPE (8); ? ({ void *__s = (s); __bzero (__s, n); __s; }) \ : memset (s, c, n)))) -# define __memset_1(s, c) ({ void *__s = (s); \ +# define __memset_1(s, c) ({ void *__s = (s); \ *((__uint8_t *) __s) = (__uint8_t) c; __s; }) -# define __memset_gc(s, c, n) \ +# define __memset_gc(s, c, n) \ ({ void *__s = (s); \ union { \ unsigned int __ui; \ @@ -177,15 +178,19 @@ __STRING2_COPY_TYPE (8); } \ \ __s; }) -# else -# define memset(s, c, n) \ +# else +# define memset(s, c, n) \ (__extension__ (__builtin_constant_p (c) && (c) == '\0' \ ? ({ void *__s = (s); __bzero (__s, n); __s; }) \ : memset (s, c, n))) +# endif # endif -/* GCC optimizes memset(s, 0, n) but not bzero(s, n). - The optimization is broken before EGCS 1.1. */ +/* GCC < 3.0 optimizes memset(s, 0, n) but not bzero(s, n). + The optimization is broken before EGCS 1.1. + GCC 3.0+ has __builtin_bzero as well, but at least till GCC 3.4 + if it decides to call the library function, it calls memset + and not bzero. */ # if __GNUC_PREREQ (2, 91) # define __bzero(s, n) __builtin_memset (s, '\0', n) # endif |