auto enter =
        ops::internal::Enter(scope.WithOpName("while/Enter"), source, "aloop");
    // Add an unused Enter node. These should be ignored.
    auto enter2 =
        ops::internal::Enter(scope.WithOpName("while/Enter2"), source, "aloop");
    auto merge = ops::Merge(scope.WithOpName("while/Merge"),
                            std::initializer_list<Input>{enter, dummy});

it does not call the loop body again after it has returned false or
after the entire loop has exited (it might retain a copy of the body
function, or pass it to another goroutine) -- each generated loop has
its own #stateK variable that is used to check for permitted call
patterns to the yield function for a loop body.

The state values are:

abi.RF_DONE = 0      // body of loop has exited in a non-panic way

	CMP   R5, $0
	MOVD  R5, CTR         // Set up loop counter
	BEQ   tail            // If R5 = 0, we can't use the loop

	// Process 4 elements per iteration. Unrolling this loop
	// means a performance trade-off: we will lose performance
	// for small values of z_len (0.90x in the worst case), but
	// gain significant performance as z_len increases (up to
	// 1.45x).

	PCALIGN $16
loop:
	MOVD  8(R8), R11      // R11 = x[i]

    TF_DeleteBuffer(buf);
    return def.DebugString();
  }

  TF_Status* s_;
  TF_Graph* graph_;
  std::vector<TF_Output> inputs_;   // The inputs to the while loop
  std::vector<TF_Output> outputs_;  // The final outputs of the while loop
  std::unique_ptr<TF_WhileParams> params_;
  std::unique_ptr<CSession> csession_;

 private:
  // Used to verify that errors don't change graph_

        max_concurrent 1000
    }
    cache 30
    loop
    reload
    loadbalance
}
`,
			coreDNSVersion: "1.6.2",
		},
		{
			name: "Default Corefile with rearranged plugins",
			initialCorefileData: `.:53 {
        errors
        cache 30
        prometheus :9153
        forward . /etc/resolv.conf
        loop
        reload
        loadbalance

  // the while loop.
  // TODO(skyewm): what if not all the exit nodes are reachable?
  if (backprops.size() < while_ctx->exit_nodes().size())
    return absl::OkStatus();

  // We've seen all the exit nodes for this loop and have collected all the
  // backprops. Create the gradient graph for the while loop.
  Scope while_scope =

	// When not surging, we delete just enough pods to stay under the maxUnavailable limit, if any
	// are necessary, and let the core loop create new instances on those nodes.
	//
	// Assumptions:
	// * Expect manage loop to allow no more than one pod per node
	// * Expect manage loop will create new pods
	// * Expect manage loop will handle failed pods
	// * Deleted pods do not count as unavailable so that updates make progress when nodes are down

      /*parallel_iterations=*/10, false,
      /*shape_invariant=*/false);

  // `_lower_using_switch_merge` is the default for While ops created
  // in TensorFlow and allows lowering to V1 control flow for loop
  // parallelization.
  dataset_while->setAttr("_lower_using_switch_merge",
                         builder.getBoolAttr(true));

  return dataset_while;
}

	HotPgoInitial          = HotPgo | HotInitial                // special case; single block loop, initial block is header block has a flow-in entry, but PGO says it is hot
	HotPgoInitialNotFLowIn = HotPgo | HotInitial | HotNotFlowIn // PGO says it is hot, and the loop is rotated so flow enters loop with a branch

            }
          }
        }
      }
    }

    // Merge node causes a loop so we remove NextIteration->Merge edge before
    // performing shape inference. But removing those edges also prevents us
    // from inferring output shape for Merge node (we need shapes for all its
    // inputs).
    // For loop invariant resource input's Merge node, we set output resource
    // shape as Enter node's resource shape.