Use CORENEURON_PREFER_OPENMP_OFFLOAD.

Author: olupton

CMake/OpenAccHelper.cmake

@@ -75,16 +75,24 @@ if(CORENRN_ENABLE_GPU)
       message(FATAL_ERROR "${CORENRN_ACCELERATOR_OFFLOAD} not supported with NVHPC compilers")
     endif()
   elseif(${CMAKE_CXX_COMPILER_ID} STREQUAL "XLClang")
-    set(NVHPC_ACC_COMP_FLAGS "-qsmp=omp -qoffload -qreport")
-    set(NVHPC_ACC_LINK_FLAGS "-qcuda -lcaliper")
-
-    if(CORENRN_ENABLE_OPENMP AND CORENRN_ENABLE_OPENMP_OFFLOAD)
+    if(CORENRN_ACCELERATOR_OFFLOAD STREQUAL "OpenMP")
+      set(NVHPC_ACC_COMP_FLAGS "-qsmp=omp -qoffload -qreport")
+      set(NVHPC_ACC_LINK_FLAGS "-qcuda -lcaliper")
       # Enable OpenMP target offload to GPU and if both OpenACC and OpenMP directives are available
       # for a region then prefer OpenMP.
-      add_compile_definitions(CORENRN_PREFER_OPENMP_OFFLOAD)
+      add_compile_definitions(CORENEURON_PREFER_OPENMP_OFFLOAD)
+    else()
+      message(FATAL_ERROR "${CORENRN_ACCELERATOR_OFFLOAD} not supported with XLClang compilers")
     endif()
   elseif(${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
-    set(NVHPC_ACC_COMP_FLAGS "-fopenmp -fopenmp-targets=nvptx64-nvidia-cuda -Wno-unknown-cuda-version -I${CUDAToolkit_INCLUDE_DIRS}")
+    if(CORENRN_ACCELERATOR_OFFLOAD STREQUAL "OpenMP")
+      set(NVHPC_ACC_COMP_FLAGS "-fopenmp -fopenmp-targets=nvptx64-nvidia-cuda -Wno-unknown-cuda-version -I${CUDAToolkit_INCLUDE_DIRS}")
+      # Enable OpenMP target offload to GPU and if both OpenACC and OpenMP directives are available
+      # for a region then prefer OpenMP.
+      add_compile_definitions(CORENEURON_PREFER_OPENMP_OFFLOAD)
+    else()
+      message(FATAL_ERROR "${CORENRN_ACCELERATOR_OFFLOAD} not supported with Clang compilers")
+    endif()
   else()
     message(FATAL_ERROR "${CMAKE_CXX_COMPILER_ID} is not supported in GPU builds.")
   endif()

coreneuron/utils/offload.hpp

@@ -9,7 +9,7 @@
 #include <cstddef>
 
 #define nrn_pragma_stringify(x) #x
-#if defined(CORENEURON_ENABLE_GPU) && defined(CORENRN_PREFER_OPENMP_OFFLOAD) && defined(_OPENMP)
+#if defined(CORENEURON_ENABLE_GPU) && defined(CORENEURON_PREFER_OPENMP_OFFLOAD) && defined(_OPENMP)
 #define nrn_pragma_acc(x)
 #define nrn_pragma_omp(x) _Pragma(nrn_pragma_stringify(omp x))
 #include <omp.h>