message: Ensure we only transform convolutions when required
  Test Plan: Tests pass
  Reviewers: georgep, jakeh, davidn
diff: @@ -154,7 +154,7 @@ poplar::Tensor DoCachedConvolution(
  // If this is a backprop input convolution perform the
  // weightsTransposeChansFlipXY on weights.
  if (conv_type == ConvClassificationType::BACKPROP_INPUT &&
  - !res.disable_graph_convolution_caching) {
  + !res.disable_graph_convolution_caching && transpose_and_flip_weights) {
  conv_type = ConvClassificationType::FORWARD;
  transpose_and_flip_weights = false;
  auto fwd_opts = GetConvolutionOptions(res, conv_type);
  