Minor correction concerning compilation compatibility with CUDA 9.0

Since CUDA 9.0 doesn't support sm_20 and sm_21 anymore. This PR allows Caffe to compile with CUDA 9.0 and newer versions successfully.
This addresses the discussion concerning [#6237](https://github.com/BVLC/caffe/pull/6237) in [master (#6237)](https://github.com/BVLC/caffe/commit/cb150eca6d593ddb85e53acd05b8dcf709ea8337#diff-2004a3d3e6b4ed2e2812bb0b4b998f18)

diff --git a/cmake/Cuda.cmake b/cmake/Cuda.cmake
index 9325674..9ced9f9 100644 (file)
--- a/cmake/Cuda.cmake
+++ b/cmake/Cuda.cmake
@@ -109,8 +109,8 @@ function(caffe_select_nvcc_arch_flags out_variable)
   set(__nvcc_flags "")
   set(__nvcc_archs_readable "")
 
-  string(COMPARE GREATER_EQUAL "${CUDA_VERSION}" "9.1" iscudanewerthan91)
-  if(iscudanewerthan91)
+  string(COMPARE GREATER_EQUAL "${CUDA_VERSION}" "9.0" iscudanewerthan90)
+  if(iscudanewerthan90)
     string(REPLACE "21(20)" "" __cuda_arch_bin "${__cuda_arch_bin}")
     string(REPLACE "20" "" __cuda_arch_bin "${__cuda_arch_bin}")
   endif()