Allow NVHPC as device compiler only with Kokkos_ENABLE_IMPL_NVHPC_AS_…

…DEVICE_COMPILER=ON

.jenkins

@@ -86,6 +86,7 @@ pipeline {
                                 -DKokkos_ENABLE_CUDA_LAMBDA=ON \
                                 -DKokkos_ENABLE_OPENMP=ON \
                                 -DKokkos_ENABLE_IMPL_MDSPAN=ON \
+                                -DKokkos_ENABLE_IMPL_NVHPC_AS_DEVICE_COMPILER=ON \
                               .. && \
                               make -j8 && ctest --verbose'''
                     }

cmake/kokkos_compiler_id.cmake

@@ -42,10 +42,13 @@ IF(Kokkos_ENABLE_CUDA)
     # If launcher was found and nvcc_wrapper was not specified as
     # compiler and `CMAKE_CXX_COMPILIER_LAUNCHER` is not set, set to use launcher.
     # Will ensure CMAKE_CXX_COMPILER is replaced by nvcc_wrapper
-    IF(Kokkos_COMPILE_LAUNCHER AND NOT INTERNAL_HAVE_COMPILER_NVCC AND NOT KOKKOS_CXX_COMPILER_ID STREQUAL Clang AND NOT KOKKOS_CXX_COMPILER_ID STREQUAL NVHPC)
+    IF(Kokkos_COMPILE_LAUNCHER AND NOT INTERNAL_HAVE_COMPILER_NVCC AND NOT KOKKOS_CXX_COMPILER_ID STREQUAL Clang
+       AND NOT (Kokkos_ENABLE_IMPL_NVHPC_AS_DEVICE_COMPILER AND KOKKOS_CXX_COMPILER_ID STREQUAL NVHPC))
       IF(CMAKE_CXX_COMPILER_LAUNCHER)
-       MESSAGE(FATAL_ERROR "Cannot use CMAKE_CXX_COMPILER_LAUNCHER if the CMAKE_CXX_COMPILER is not able to compile CUDA code, i.e. nvcc_wrapper or
-clang++!")
+        IF(KOKKOS_CXX_COMPILER_ID STREQUAL NVHPC)
+          MESSAGE(STATUS "Using nvc++ as device compiler requires Kokkos_ENABLE_IMPL_NVHPC_AS_DEVICE_COMPILER=ON!")
+        ENDIF()
+        MESSAGE(FATAL_ERROR "Cannot use CMAKE_CXX_COMPILER_LAUNCHER if the CMAKE_CXX_COMPILER is not able to compile CUDA code, i.e. nvcc_wrapper or clang++!")
       ENDIF()
       # the first argument to launcher is always the C++ compiler defined by cmake
       # if the second argument matches the C++ compiler, it forwards the rest of the

cmake/kokkos_enable_options.cmake

@@ -47,6 +47,7 @@ KOKKOS_ENABLE_OPTION(CUDA_LAMBDA ${CUDA_LAMBDA_DEFAULT} "Whether to allow lambda
 # the past when UCX was used as MPI communication layer.  We expect it is
 # resolved but we keep the option around a bit longer to be safe.
 KOKKOS_ENABLE_OPTION(IMPL_CUDA_MALLOC_ASYNC ON  "Whether to enable CudaMallocAsync (requires CUDA Toolkit 11.2)")
+KOKKOS_ENABLE_OPTION(IMPL_NVHPC_AS_DEVICE_COMPILER OFF "Whether to allow nvc++ as Cuda device compiler")
 KOKKOS_ENABLE_OPTION(DEPRECATED_CODE_3    OFF "Whether code deprecated in major release 3 is available" )
 KOKKOS_ENABLE_OPTION(DEPRECATED_CODE_4    ON "Whether code deprecated in major release 4 is available" )
 KOKKOS_ENABLE_OPTION(DEPRECATION_WARNINGS ON "Whether to emit deprecation warnings" )

cmake/kokkos_test_cxx_std.cmake

@@ -120,8 +120,12 @@ IF(KOKKOS_ENABLE_CUDA)
     ELSEIF(CMAKE_CXX_EXTENSIONS)
       MESSAGE(FATAL_ERROR "Compiling CUDA code with clang doesn't support C++ extensions.  Set -DCMAKE_CXX_EXTENSIONS=OFF")
     ENDIF()
-  ELSEIF(NOT KOKKOS_CXX_COMPILER_ID STREQUAL NVIDIA AND NOT KOKKOS_CXX_COMPILER_ID STREQUAL NVHPC)
-    MESSAGE(FATAL_ERROR "Invalid compiler for CUDA.  The compiler must be nvcc_wrapper or Clang or NVC++ or use kokkos_launch_compiler, but compiler ID was ${KOKKOS_CXX_COMPILER_ID}")
+  ELSEIF(NOT KOKKOS_CXX_COMPILER_ID STREQUAL NVIDIA AND NOT (Kokkos_ENABLE_IMPL_NVHPC_AS_DEVICE_COMPILER AND KOKKOS_CXX_COMPILER_ID STREQUAL NVHPC))
+    IF(KOKKOS_CXX_COMPILER_ID STREQUAL NVHPC)
+      MESSAGE(FATAL_ERROR "Invalid compiler for CUDA. To allow nvc++ as Cuda compiler, Kokkos_ENABLE_IMPL_NVHPC_AS_DEVICE_COMPILER=ON must be set!")
+    ELSE()
+      MESSAGE(FATAL_ERROR "Invalid compiler for CUDA. The compiler must be nvcc_wrapper or Clang or NVC++ or use kokkos_launch_compiler, but compiler ID was ${KOKKOS_CXX_COMPILER_ID}")
+    ENDIF()
   ENDIF()
 ENDIF()