Move --expt-relaxed-constexpt as a NVCC flag

cmake/configure.cmake

@@ -60,7 +60,7 @@ else()
         message(FATAL_ERROR "Paddle need cudnn to compile")
     endif()
 
-    set(CUDA_NVCC_FLAGS ${CUDA_NVCC_FLAGS} "-Xcompiler ${SIMD_FLAG}")
+    set(CUDA_NVCC_FLAGS ${CUDA_NVCC_FLAGS} "-Xcompiler ${SIMD_FLAG}" "--expt-relaxed-constexpr")
 
     # Include cuda and cudnn
     include_directories(${CUDNN_INCLUDE_DIR})

cmake/flags.cmake

@@ -116,7 +116,6 @@ set(COMMON_FLAGS
     -Wno-error=sign-compare
     -Wno-error=unused-local-typedefs
     -Wno-error=parentheses-equality # Warnings in pybind11
-    --expt-relaxed-constexpr # surppress warnings in Eigen
 )
 
 set(GPU_COMMON_FLAGS
@@ -131,7 +130,6 @@ set(GPU_COMMON_FLAGS
     -Wno-error=unused-local-typedefs
     -Wno-error=unused-function  # Warnings in Numpy Header.
     -Wno-error=array-bounds # Warnings in Eigen::array
-    --expt-relaxed-constexpr # surppress warnings in Eigen
 )
 
 if (APPLE)