// 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();
    }

//     (c) `cond` is a vector AND `then` and `else` are non-scalar with their
//         first dimension equal to `cond`.
LogicalResult SelectOp::verify() {
  SelectOp op = *this;
  auto then_tensor = op.getThenValue().getType().cast<TensorType>();
  auto else_tensor = op.getElseValue().getType().cast<TensorType>();
  // Check (1).
  if (!AreCastCompatible({then_tensor, else_tensor}))