src/etc/platform-intrinsics/nvptx/cuda.json

{
    "intrinsic_prefix": "_",
    "llvm_prefix": "llvm.cuda.",
    "intrinsics": [
        {
            "intrinsic": "syncthreads",
            "width": ["0"],
            "llvm": "syncthreads",
            "ret": "V",
            "args": []
        }
    ]
}