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authorUlrich Drepper <drepper@redhat.com>1999-04-30 09:36:37 +0000
committerUlrich Drepper <drepper@redhat.com>1999-04-30 09:36:37 +0000
commitc1d226e77feae34514c93caef49369b0e94f83cb (patch)
treea93a3b06867695f60cc3c61ec81ed6181f3d2420 /string/bits
parent9943472996fdf9b881550ee75673aae0a080e214 (diff)
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Update.
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.
Diffstat (limited to 'string/bits')
-rw-r--r--string/bits/string2.h13
1 files changed, 10 insertions, 3 deletions
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