CheckComputeCapability.cmake

#############################
# Check for GPUs present and their compute capability
# based on http://stackoverflow.com/questions/2285185/easiest-way-to-test-for-existence-of-cuda-capable-gpu-from-cmake/2297877#2297877 (Christopher Bruns)
if(CUDA_FOUND)
	message(STATUS "${CMAKE_SOURCE_DIR}/cuda_compute_capability.c")
	try_run(RUN_RESULT_VAR COMPILE_RESULT_VAR
		${CMAKE_BINARY_DIR} 
		${CMAKE_SOURCE_DIR}/cuda_compute_capability.c
		CMAKE_FLAGS 
		-DINCLUDE_DIRECTORIES:STRING=${CUDA_TOOLKIT_INCLUDE}
		-DLINK_LIBRARIES:STRING=${CUDA_CUDART_LIBRARY}
		COMPILE_OUTPUT_VARIABLE COMPILE_OUTPUT_VAR
		RUN_OUTPUT_VARIABLE RUN_OUTPUT_VAR)
	message(STATUS "Compile: ${RUN_OUTPUT_VAR}")
	if (COMPILE_RESULT_VAR)
		message(STATUS "compiled -> " ${RUN_RESULT_VAR})
	else()
		message(STATUS "didn't compile")
	endif()
	# COMPILE_RESULT_VAR is TRUE when compile succeeds
	# RUN_RESULT_VAR is zero when a GPU is found
	if(COMPILE_RESULT_VAR AND NOT RUN_RESULT_VAR)
		message(STATUS "worked")
		set(CUDA_HAVE_GPU TRUE CACHE BOOL "Whether CUDA-capable GPU is present")
		set(CUDA_COMPUTE_CAPABILITY ${RUN_OUTPUT_VAR} CACHE STRING "Compute capability of CUDA-capable GPU present")
		set(CUDA_GENERATE_CODE "arch=compute_${CUDA_COMPUTE_CAPABILITY},code=sm_${CUDA_COMPUTE_CAPABILITY}" CACHE STRING "Which GPU architectures to generate code for (each arch/code pair will be passed as --generate-code option to nvcc, separate multiple pairs by ;)")
		mark_as_advanced(CUDA_COMPUTE_CAPABILITY CUDA_GENERATE_CODE)
		set(CUDA_NVCC_FLAGS ${CUDA_NVCC_FLAGS} -arch compute_${CUDA_COMPUTE_CAPABILITY})
	else()
		message(STATUS "didn't work")
		set(CUDA_HAVE_GPU FALSE CACHE BOOL "Whether CUDA-capable GPU is present")
	endif()
endif()