ref: f080353c96b53a7b881f470d8e8f6e1151fa6524
dir: /builtins.c/
int
__builtin_clz(unsigned int x)
{
unsigned int r;
if(x == 0)
return 32;
for(r = 0; (x & (1UL<<31)) == 0; x <<= 1, r++);
return r;
}
int
__builtin_clzll(unsigned long long x)
{
unsigned long long r;
if(x == 0)
return 64;
for(r = 0; (x & (1ULL<<63)) == 0; x <<= 1, r++);
return r;
}