Created by: wangkuiyi

In the class template DimGetter, there are two signatures of impl:

https://github.com/PaddlePaddle/Paddle/blob/8dbd9c394e9cb97926320e113b112431ef509ec5/paddle/fluid/framework/dim.h#L109-L122

cpplint complains about the second impl because its parameter is not a const reference:

dim.h:118:  Is this a non-const reference? If so, make const or use a pointer: D& d  [runtime/references] [2]

This complaint intrigues us to think of the correct design:

• The purpose of the first impl is to get, whereas the second is for *set, so

• we should move the second impl into a new class template DimSetter:

  template <int i>
  struct DimSetter {
    HOSTDEVICE static void impl(const D&d, int64_t v) {
    ...