Re: [PATCH] lib/int_sqrt.c: Optimize square root function

[Joe Perches]

On Fri, 2017-07-21 at 13:40 +0200, Peter Zijlstra wrote:
> @@ -21,7 +22,11 @@ unsigned long int_sqrt(unsigned long x)
>  	if (x <= 1)
>  		return x;
>  
> -	m = 1UL << (BITS_PER_LONG - 2);
> +	m = 1UL << (__fls(x) & ~1U);
> +
> +	while (m > x)
> +		m >>= 2;

while (m > x) ?

Belt and suspenders if __fls is broken?