def _compile_function(self, fn, arg_tys):
        """
        Compile the given function both without and with rewrites enabled.
        """
        control_pipeline = RewritesTester.mk_no_rw_pipeline(arg_tys)
        cres_0 = control_pipeline.compile_extra(fn)
        control_cfunc = cres_0.entry_point

        test_pipeline = RewritesTester.mk_pipeline(arg_tys)
        cres_1 = test_pipeline.compile_extra(fn)
        test_cfunc = cres_1.entry_point

        return control_pipeline, control_cfunc, test_pipeline, test_cfunc

        Compile the given function both without and with rewrites enabled.
        
numba/tests/test_array_exprs.py