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?