+linux-kernel
> +#define DECLARE_EWMA(name, _factor, _weight)> > > >
> > \
> +> > struct ewma_##name {> > > > > >
> > \
> +> > > unsigned long internal;> > > > >
> > \
> +> > };> > > > > > > > > \
> +> > static inline void ewma_##name##_init(struct ewma_##name *e)>
> > \
> +> > {> > > > > > > > > \
> +> > > BUILD_BUG_ON(!__builtin_constant_p(_factor));> >
> > \
> +> > > BUILD_BUG_ON(!__builtin_constant_p(_weight));> >
> > \
> +> > > BUILD_BUG_ON(!is_power_of_2(_factor));> > >
> > \
> +> > > BUILD_BUG_ON(!is_power_of_2(_weight));> > >
> > \
>
So this seemed fine to me, but for some reason the compiler is saying
the BUILD_BUG_ON(!is_power_of_2(x)) fails, if and only if (!)
CONFIG_GCOV_PROFILE_ALL is enabled, which seems to boil down to the
compiler option -fprofile-arcs.
I'm going to replace this with just the code itself, i.e.
/* both must be a power of 2 */
BUILD_BUG_ON(_factor & (_factor - 1));
BUILD_BUG_ON(_weight & (_weight - 1));
but should I have expected this?
johannes
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