Function rustc_codegen_llvm::intrinsic::gen_fn

fn gen_fn<'ll, 'tcx>(
    cx: &CodegenCx<'ll, 'tcx>, 
    name: &str, 
    inputs: Vec<Ty<'tcx>>, 
    output: Ty<'tcx>, 
    codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>)
) -> &'ll Value