change __shfl_down_sync() to __shfl_down

Hello I'm new commer in apex nvidia.

I supposed to install apex but my cuda version is 8.0 so cannot installed it.
and in my situation I cannot change my cuda version to 9.0 or over(because of my project doing now)

so I tried to install the apex using
**pip install -v --no-cache-dir --global-option="--cpp_ext" --global-option="--cuda_ext" ./**

command but since I cannot use cuda 9.0 or over, error is occurred like this

**csrc/type_shim.h(170): error: identifier "__shfl_down_sync" is undefined

    1 error detected in the compilation of "/tmp/tmpxft_00000a0e_00000000-7_multi_tensor_scale_kernel.cpp1.ii".
    error: command u'/usr/local/cuda/bin/nvcc' failed with exit status 2**

so I changed shfl_down_sync to shfl_down to install apex but the error message is similar like before, only changed message is "__shfl_down" is undefined

how can I solve this problem?
my linux version is 16.04 and cuda is 8.0
I really appreciate your answer. thanks

Start with csrc/type_shim.h around line 170 and reproduce the reported build using CUDA 8.0 and the listed pip command. Trace how the shuffle intrinsic is selected for the CUDA extension, then use the compilation result to define a compatible change and verify that the extension builds successfully on the stated environment.