// This lowering only works on ranked types.
    auto cond_type =
        mlir::dyn_cast<RankedTensorType>(op.getCondition().getType());
    auto then_type =
        mlir::dyn_cast<RankedTensorType>(op.getThenValue().getType());
    auto else_type =
        mlir::dyn_cast<RankedTensorType>(op.getElseValue().getType());
    if (!cond_type || !then_type || !else_type) {
      return failure();
    }