Addressed PR review comments

aten/src/ATen/native/cpu/UpSampleKernelAVXAntialias.h

@@ -363,8 +363,8 @@ void upsample_avx_bilinear_uint8(
   at::Tensor buffer_horiz, buffer_vert;
   // Minor optimization: we can avoid allocating an extra buffer if we're performing
   // horizontal-only or vertical-only interpolation, and if the tensor doesn't
-  // need unpacking
-  if (need_horizontal && !(skip_packing && !need_vertical)) {
+  // need repacking
+  if (need_horizontal && (need_vertical || !skip_packing)) {
     auto c = (skip_unpacking) ? num_channels : 4;
     buffer_horiz = at::empty({c, yin, xout}, input.options());
   }
@@ -379,7 +379,7 @@ void upsample_avx_bilinear_uint8(
     at::Tensor unpacked_output;
 
     if (need_horizontal) {
-      at::Tensor unpacked_output_temp = (skip_packing && !need_vertical) ? output[i] : buffer_horiz;
+      at::Tensor unpacked_output_temp = (need_vertical || !skip_packing) ? buffer_horiz : output[i];
 
       if (skip_unpacking && num_channels == 3) {
         ImagingResampleHorizontal<3>(

test/test_nn.py

@@ -9698,7 +9698,9 @@ def test_upsamplingBiLinear2d_consistency(
             input_ui8, size=(output_size, output_size), mode=mode, align_corners=align_corners, antialias=antialias
         )
 
-        # Check if output is CF for unsqueezed 3d CL tensor
+        # FIXME if-clause shows the current behaviour which is definitely unexpected.
+        # Ideally we want to fix it such that both the ui8 and f32 outputs are also channels_last
+        # See for more details: https://github.com/pytorch/pytorch/pull/100373
         if check_as_unsqueezed_3d_tensor and memory_format == torch.channels_last:
             self.assertTrue(input_ui8.is_contiguous(memory_format=torch.channels_last))
             self.assertTrue(output_ui8.is_contiguous())