[%6, %7] as %input_3: tensor<!tf_type.string>,
                                %8 as %input_4: tensor<!tf_type.variant>)
                {n = 2 : i32,
                 devices = {DEVICE_ALIAS_0 = ["/DEVICE:0", "/DEVICE:1"],
                            DEVICE_ALIAS_1 = ["/DEVICE:2", "/DEVICE:3"]}} {
  // Inside the region, %0, %2, %4, and %6 corresponds to

//              {n = 2 : i32,
//               devices = {DEVICE_ALIAS_0 = ["/DEVICE:0", "/DEVICE:1"],
//                          DEVICE_ALIAS_1 = ["/DEVICE:2", "/DEVICE:3"]}} {
//     %a = "tf_device.launch"() ({
//       %2 = "tf.opA"(%ri) : (tensor<i1>) -> tensor<i1>
//       tf_device.return %2 : tensor<i1>
//     }) {device = "DEVICE_ALIAS_0"} : () -> tensor<i1>
//     %b = "tf_device.launch"() ({