static inline int clz64(unsigned long val)
{
	return val ? __builtin_clzll(val) : 64;
}

static inline int is_power_of_2(unsigned long value)
{
	if (!value)
		return 0;

	return !(value & (value - 1));
}

long pow2floor(long value)
{
	if (!is_power_of_2(value))
		value = 0x8000000000000000ULL >> clz64(value);

	return value;
}

unsigned foo(unsigned max, unsigned size)
{
	if (size > max)
		size = max;
	size = pow2floor(size);
	return size;
}

int main(void)
{
	unsigned i, l, max;
	volatile val;

	for (i = 0; i < 100000000; i++) {
		for (max = 1; max <= 8; max <<= 1) {
			for (l = 1; l <= 8; l++)
				val = foo(max, l);
		}
	}
	return 0;
}