Function GetValueBitCountImpl

util/generic/bitops.h:61–64

#if defined(__GNUC__)
        inline unsigned GetValueBitCountImpl(unsigned int value) noexcept {
            Y_ASSERT(value); // because __builtin_clz* have undefined result for zero.
            return std::numeric_limits<unsigned int>::digits - __builtin_clz(value);
        }

        inline unsigned GetValueBitCountImpl(unsigned long value) noexcept {
            Y_ASSERT(value); // because __builtin_clz* have undefined result for zero.