gcc 4.3.2 miscompiles byte_diff :-(

master
leitner 16 years ago
parent 3636c04609
commit 4678c3c08e

@ -6,6 +6,8 @@
* one[len-1]. When the strings are different, byte_diff does not read * one[len-1]. When the strings are different, byte_diff does not read
* bytes past the first difference. */ * bytes past the first difference. */
int byte_diff(const void* a, size_t len, const void* b) { int byte_diff(const void* a, size_t len, const void* b) {
#if 0
/* this gets miscompiled by gcc 4.3.2 on x86_64 */
register const unsigned char* s=a; register const unsigned char* s=a;
register const unsigned char* t=b; register const unsigned char* t=b;
register const unsigned char* u=t+len; register const unsigned char* u=t+len;
@ -18,4 +20,12 @@ int byte_diff(const void* a, size_t len, const void* b) {
if (t==u) break; if ((j=((unsigned int)*s-*t))) break; ++s; ++t; if (t==u) break; if ((j=((unsigned int)*s-*t))) break; ++s; ++t;
} }
return j; return j;
#else
size_t i;
for (i=0; i<len; ++i) {
int r=((unsigned char*)a)[i] - ((unsigned char*)b)[i];
if (r) return r;
}
return 0;
#endif
} }

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