// AssignVariableOp.

// expected-error@+1 {{expects users of resource argument 0 to be 'tf.ReadVariableOp' or 'tf.AssignVariableOp', got [tf.UnknownOp, tf.VarIsInitializedOp]}}
func.func @main(%arg0: tensor<!tf_type.resource<tensor<f32>>>) -> tensor<i1> {
  %0 = "tf.VarIsInitializedOp"(%arg0) : (tensor<!tf_type.resource<tensor<f32>>>) -> tensor<i1>
  %1 = "tf.UnknownOp"(%arg0) : (tensor<!tf_type.resource<tensor<f32>>>) -> tensor<i1>

      %6 = "tf.VarIsInitializedOp"(%arg0) : (!tf_res) -> tensor<i1>
      // CHECK-NEXT: "tf.Yield"([[IF_REGION_THEN]])
      "tf.Yield"(%6) : (tensor<i1>) -> ()
    // CHECK-NEXT: }, {
    }, {
      // CHECK-NEXT: [[IF_REGION_ELSE:%.+]] = "tf.Const"
      // CHECK-SAME: value = dense<true> : tensor<i1>
      %7 = "tf.VarIsInitializedOp"(%arg0) : (!tf_res) -> tensor<i1>

  auto subtypes = resource_type.getSubtypes();
  if (subtypes.size() == 1) return subtypes[0];
  return nullptr;
}

// Replaces all `tf.VarIsInitializedOp` in a block with a constant true.
// TODO(b/171039585): Replace this with proper analysis of
// `tf.VarIsInitializedOp` in regards to resource writes and control flow.
void SetAllVarIsInitializedToTrue(Block* block) {
  auto builder = OpBuilder::atBlockBegin(block);

// VarIsInitializedOp
//===----------------------------------------------------------------------===//

namespace {

/// Erase VarIsInitializedOp operations with no uses. This op has side effect on
/// resources (read-only), but can still be deleted if it has zero uses.
struct EraseDeadVarIsInitializedOp
    : public OpRewritePattern<VarIsInitializedOp> {

  %is = "tf.VarIsInitializedOp"(%vh) : (tensor<!tf_type.resource<tensor<f32>>>) -> tensor<i1>
  %res = "tf.UnknownOp"(%vh) : (tensor<!tf_type.resource<tensor<f32>>>) -> tensor<i1>
  func.return %res : tensor<i1>
}
// Unused VarIsInitializedOp is erased.
// CHECK: tf.VarHandleOp
// CHECK-NEXT: tf.UnknownOp

      "Unique",
      "UniqueV2",
      "UpperBound",
      "UnsortedSegmentMax",
      "UnsortedSegmentMin",
      "UnsortedSegmentProd",
      "UnsortedSegmentSum",
      "VarIsInitializedOp",
      "VariableShape",
      "Where",
      "While",
      "XlaAllReduce",
      "XlaBroadcastHelper",
      "XlaCallModule",
      "XlaConcatND",
      "XlaConv",
      "XlaConvV2",

  );

  TF_DerivedOperandTypeAttr T = TF_DerivedOperandTypeAttr<0>;
  TF_DerivedResultTypeAttr out_type = TF_DerivedResultTypeAttr<0>;
}

def TF_VarIsInitializedOp : TF_Op<"VarIsInitializedOp", []> {
  let summary = [{
Checks whether a resource handle-based variable has been initialized.
  }];

  let arguments = (ins