message: Incorporate Thomas's comments
diff: @@ -251,16 +251,17 @@ MatchBackwardFilter(HloInstruction* conv) {
  return std::make_tuple(true, backward_conv_window, backward_conv_dnums,
  lhs);
  }
  - Shape new_shape = lhs->shape();
  int64 input_batch_dimension = backward_conv_dnums.input_batch_dimension();
  int64 input_feature_dimension = backward_conv_dnums.input_feature_dimension();
  - int64 input_batch = new_shape.dimensions(input_batch_dimension);
  - int64 input_feature = new_shape.dimensions(input_feature_dimension);
  -
  + int64 input_batch = lhs->shape().dimensions(input_batch_dimension);
  // Ensure that input_batch is exact multiple of conv->feature_group_count()
  - CHECK_EQ(input_batch % conv->feature_group_count(), 0);
  + CHECK_EQ(input_batch % conv->feature_group_count(), 0)
  + << "Input batch should be an exact multiple of feature group count";
  + int64 input_feature = lhs->shape().dimensions(input_feature_dimension);
  +
  + Shape new_shape = lhs->shape();
  new_shape.set_dimensions(input_batch_dimension,
  input_batch / conv->feature_group_count());
  new_shape.set_dimensions(input_feature_dimension,
  