return value.getDefiningOp();
}

// Check if the TPUCopyWithDynamicShapeOp is valid.
// 1. The op should be wrapped inside a launch op.
// 2. The wrapped launch op should be placed on CPU.
LogicalResult CheckOpIsValid(Operation* op) {
  auto launch_op = llvm::dyn_cast<tf_device::LaunchOp>(op->getParentOp());
  if (!launch_op) {
    op->emitError() << "TPUCopyWithDynamicShapeOp is not in a launch";
  }

  solver.load<dataflow::SparseConstantPropagation>();
  solver.load<DeviceDataflowAnalysis>(symbolTables);
  if (failed(solver.initializeAndRun(module))) return signalPassFailure();

  module->walk([&](TF::TPUCopyWithDynamicShapeOp op) {
    const Device *state;
    for (auto result : op->getResults()) {
      state = solver.lookupState<Device>(result);
      if (state) break;
    }
    if (!state || !state->hasDevice()) {