Function AlignDown

Bcore/src/main/cpp/base/bit_utils.h:182–184

template<typename T>
inline T* AlignDown(T* x, uintptr_t n) {
  return reinterpret_cast<T*>(RoundDown(reinterpret_cast<uintptr_t>(x), n));
}

template<typename T>
inline T* AlignUp(T* x, uintptr_t n) WARN_UNUSED;