diff options
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | string/bits/string2.h | 13 |
2 files changed, 17 insertions, 3 deletions
@@ -1,3 +1,10 @@ +1999-04-30 09:02 -0400 Zack Weinberg <zack@rabi.columbia.edu> + + * string/bits/string2.h (memset): Avoid arithmetic overflow at + compile time, which produces obnoxious warnings. If GCCv2 is + in use, map __bzero to __builtin_memset to enable that + optimization. + 1999-04-29 Ulrich Drepper <drepper@cygnus.com> * string/bits/string2.h: Add more memset optimizations. diff --git a/string/bits/string2.h b/string/bits/string2.h index d9ed80b3b5..391859a91b 100644 --- a/string/bits/string2.h +++ b/string/bits/string2.h @@ -95,13 +95,15 @@ __STRING2_COPY_TYPE (8); #ifndef _HAVE_STRING_ARCH_memset # define memset(s, c, n) \ (__extension__ (__builtin_constant_p (n) && (n) <= 16 \ - ? (__builtin_constant_p (c) \ - ? __memset_gc (s, (c) * 0x01010101, n) \ - : __memset_gc (s, (n) == 1 ? (c) : (c) * 0x01010101, n)) \ + ? ((n) == 1 \ + ? __memset_1 (s, c) \ + : __memset_gc (s, (((__uint8_t) c) * 0x1010101), n)) \ : (__builtin_constant_p (c) && (c) == '\0' \ ? ({ void *__s = (s); __bzero (__s, n); __s; }) \ : memset (s, c, n)))) +#define __memset_1(s, c) ({ void *__s = (s); *((__uint8_t *) __s) = c; __s; }) + #define __memset_gc(s, c, n) \ ({ void *__s = (s); \ __uint32_t *__ts = (__uint32_t *) __s; \ @@ -153,6 +155,11 @@ __STRING2_COPY_TYPE (8); } \ \ __s; }) +/* GCC optimizes memset(s, 0, n) but not bzero(s, n). */ +#if defined __GNUC__ && __GNUC__ >= 2 +# define __bzero(s, n) __builtin_memset(s, '\0', n) +#endif + #endif |