auto filter_ty = mlir::dyn_cast<RankedTensorType>(op.getFilter().getType());

    // With the exception of out_backprop's batch dimension, out_backprop and
    // filter need to have static shape. Filter is validated here, out_backprop
    // is mostly validated at use.
    if (!out_backprop_ty || !filter_ty || !filter_ty.hasStaticShape())
      return failure();