// Tests loop with resource that is unique per iteration.
//
// In cases where a resource-allocating op creates a new unique resource per
// loop iteration (ops with `TF_UniqueResourceAllocation` trait, in this case:
// `tf.StackV2`), make sure that we don't create data dependencies between
// different iterations for such resources. This is in line with the behavior
// for the same loop unrolled. In this particular case, no data chain and token

  func.return
}

// CHECK-LABEL: func @ignore_stack_ops
func.func @ignore_stack_ops(%arg0: tensor<i32>) -> () {
  "tf_device.cluster"() ({
    // CHECK: "tf.StackV2"
    // CHECK-NOT: _xla_outside_compilation
    %0 = "tf.StackV2"(%arg0) {elem_type = f32, stack_name = "s"} : (tensor<i32>) -> tensor<!tf_type.resource>
    tf_device.return

  %2 = "tf.Const"() {value = dense<1> : tensor<i32>} : () -> tensor<i32>
  %3 = "tf.Const"() {value = dense<2> : tensor<i32>} : () -> tensor<i32>
  %4 = "tf.StackV2"(%3) {elem_type = f32, stack_name = "s"} : (tensor<i32>) -> tensor<!tf_type.resource>
  %5:5 = "tfl.while"(%2, %3, %2, %4, %0) ({

      "SpaceToBatch",
      "SpaceToBatchND",
      "SpaceToDepth",
      "SparseMatMul",
      "SparseToDense",
      "StackCloseV2",
      "StackPopV2",
      "StackPushV2",
      "StackV2",
      "StatefulPartitionedCall",
      "StatefulStandardNormalV2",
      "StatefulTruncatedNormal",
      "StatefulUniform",
      "StatefulUniformFullInt",
      "StatefulUniformInt",

    maximum size needs to be a constant and 2) a push op can be found with a
    known shape, and all push ops need to have the same shape.

    A stack creation op "tf.StackV2" will be turned in to two zero-initialized
    variables, for the buffer and current size. Each push will be turned into
    ```mlir
      %old_val = "tf.ReadVariableOp"(%buffer)
      %old_size = "tf.ReadVariableOp"(%size)

  let results = (outs
    Res<TF_Tensor, [{The same tensor as the input 'elem'.}]>:$output
  );

  TF_DerivedOperandTypeAttr T = TF_DerivedOperandTypeAttr<1>;
}

def TF_StackV2Op : TF_Op<"StackV2", [TF_UniqueResourceAllocation]> {
  let summary = "A stack that produces elements in first-in last-out order.";

  let arguments = (ins