func.func @invalid_yield(%arg0: tensor<*xf32>, %ctl: !tf_executor.control) {
  tf_executor.graph {
    "tf_executor.island"() ({
      "tf_executor.yield"(%arg0, %ctl) : (tensor<*xf32>, !tf_executor.control) -> ()
// expected-error@-1 {{'tf_executor.yield' op unexpected control type for operand #1}}
    }) : () -> (tensor<*xf32>, !tf_executor.control, !tf_executor.control)
  }
  func.return
}

  %result = tf_executor.graph {
// CHECK: tf_executor.Switch %{{[^%]*}}, %{{[^%]*}}, %{{[^%]*}}, %{{[^%]*}} : tensor<i1>
    %1:3 = tf_executor.Switch %arg0, %arg0, %arg1, %arg2 : (tensor<i1>, tensor<i1>, !tf_executor.control, !tf_executor.control) -> (tensor<i1>, tensor<i1>, !tf_executor.control)
    tf_executor.fetch %1#0 : tensor<i1>
  }

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

// TensorFlow Executor Type Constraint
//===----------------------------------------------------------------------===//

// Predicate to verify all control inputs appear after any non-control inputs.
def ControlOperandsAfterAllData :
    PredOpTrait<"all control inputs must appear after any non-control input",
                CPred<"succeeded(VerifyControlOperandsAfterAllData(&$_op))">>;

      the copyright owner that is granting the License.

      "Legal Entity" shall mean the union of the acting entity and all
      other entities that control, are controlled by, or are under common
      control with that entity. For the purposes of this definition,
      "control" means (i) the power, direct or indirect, to cause the
      direction or management of such entity, whether by contract or

  }

  if (auto is_stateless = op->getAttrOfType<BoolAttr>("is_stateless")) {
    return !is_stateless.getValue();
  }
  return false;
}

// Add control dependencies from stateful control-flow ops to graph fetch op.
// This is needed to avoid that such control-flow ops get pruned because of a
// bug in common runtime (see b/185483669).
void AddStatefulControlFlowDependencies(tf_executor::GraphOp graph_op) {

 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

func (t *worklist) propagate(block *Block) {
	switch block.Kind {
	case BlockExit, BlockRet, BlockRetJmp, BlockInvalid:
		// control flow ends, do nothing then
		break
	case BlockDefer:
		// we know nothing about control flow, add all branch destinations
		t.edges = append(t.edges, block.Succs...)
	case BlockFirst:
		fallthrough // always takes the first branch
	case BlockPlain:

// ```
//
// `%merged_control` is a NoOp control barrier in this case.
//
// Checks if the value `control` is a NoOp control barrier.
bool IsNoOpControlBarrier(Value control) {
  if (!mlir::isa<ControlType>(control.getType())) return false;

  auto control_island = dyn_cast_or_null<IslandOp>(control.getDefiningOp());
  if (!control_island) return false;

  // All islands perfectly wrap a single op is an invariant of this pass and