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    SubjectRe: [PATCH] Optimize is_power_of_2().
    On Fri, 15 Jun 2007 21:47:50 +0200 (CEST)
    Jan Engelhardt <jengelh@computergmbh.de> wrote:

    > On Jun 15 2007 18:56, Vegard Nossum wrote:
    > > bool is_power_of_2(unsigned long n)
    > > {
    > >- return (n != 0 && ((n & (n - 1)) == 0));
    > >+ return n * !(n & (n - 1));
    > > }
    >
    > There is a third way which uses neither * nor &&, but []:

    I assume using something GCC-specific is right out?

    bool is_power_of_to(unsigned long n)
    {
    return __builtin_ffsl(n) == 1;
    }

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