Automatic CMake CPU Feature Detection

Usage

Copy CPUFeatureDetect.cmake to your project directory.

Add to your CMakeLists.txt:

include(${PROJECT_SOURCE_DIR}/CPUFeatureDetect.cmake)

Call genCPUFeatures(namespace) to generate variables describing the current build environment's CPU capabilities.

genCPUFeatures(MyProject)
if(MyProject_FEATURE_AVX2)
    message(STATUS "[MyProject] Building with AVX2...")
    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mavx2")
else()
    message(STATUS "[MyProject] AVX2 not found!")
endif()

How It Works

We parse the llvm compiler CPU feature list (see ./generateCPUDetailsToFeatures.py) for all possible CPU features to generate CPUFeatureDetect.cmake, then when you run the genCPUFeatures() CMake function, we call potentially dozens of check_c_source_compiles() checks against all the compile feature flags to determine which CPU features are available given your current CFLAGS configuration.

If you don't have -march= specified or you request -march=native, we run all the CPU check test programs to determine your capability. If you do specify a -march= option, we use the CPU architecture name to determine which feature are available without running any test programs (for cross compiling, etc).