if (while_op->getNumRegions() != 2) return failure();

    // This rule doesn't support mhlo::WhileOp with tuple inputs.
    for (auto type : while_op->getOperandTypes()) {
      if (mlir::isa<TupleType>(type)) return failure();
    }

    // Creates a TF::WhileRegionOp to replace the mhlo::WhileOp. HLO WhileOp
    // currently doesn't support stateless and shape invariant, so these