Add no GPU support comment

Author: Meinersbur

flang-rt/CMakeLists.txt

@@ -102,19 +102,23 @@ endif ()
 option(FLANG_RT_INCLUDE_TESTS "Generate build targets for the flang-rt unit and regression-tests." "${LLVM_INCLUDE_TESTS}")
 
 
-set(FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT "" CACHE STRING "Compile flang-rt with GPU support (CUDA or OpenMP)")
+set(FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT "" CACHE STRING "Compile Flang-RT with GPU support (CUDA or OpenMP)")
 set_property(CACHE FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT PROPERTY STRINGS
     ""
     CUDA
     OpenMP
   )
 if (NOT FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT)
+  # Support for GPUs disabled
 elseif (FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT STREQUAL "CUDA")
+  # Support for CUDA
   set(FLANG_RT_LIBCUDACXX_PATH "" CACHE PATH "Path to libcu++ package installation")
   option(FLANG_RT_CUDA_RUNTIME_PTX_WITHOUT_GLOBAL_VARS "Do not compile global variables' definitions when producing PTX library" OFF)
 elseif (FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT STREQUAL "OpenMP")
-set(FLANG_RT_DEVICE_ARCHITECTURES "all" CACHE STRING
-  "List of OpenMP device architectures to be used to compile the Fortran runtime (e.g. 'gfx1103;sm_90')")
+  # Support for OpenMP offloading
+  set(FLANG_RT_DEVICE_ARCHITECTURES "all" CACHE STRING
+      "List of OpenMP device architectures to be used to compile the Fortran runtime (e.g. 'gfx1103;sm_90')"
+    )
 else ()
   message(FATAL_ERROR "Invalid value '${FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT}' for FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT; must be empty, 'CUDA', or 'OpenMP'")
 endif ()