Use 'computeStorageNbytesContiguous' to get the size just when src is…

… a view

aten/src/ATen/native/mps/operations/Copy.mm

@@ -155,21 +155,23 @@ void copy_cast_mps(at::Tensor& dst, const at::Tensor& src,
  id<MTLDevice> device = MPSDevice::getInstance()->device();
  auto dst_byte_offset = dst_.storage_offset() * dst_.itemsize();
  id<MTLBuffer> destBuffer = getMTLBufferStorage(dst_);
+ uint64_t size = 0;
 
  if (src_.is_view()) {
  src = src_.to(dst_.dtype()).expand_as(dst_).contiguous();
+ // Get the actual size of a View (takes into account the storage offset)
+ // For View tensors, the storage offset can be bigger than what's being reported by nbytes
+ size = at::detail::computeStorageNbytesContiguous(src.sizes(), src.element_size(), src.storage_offset());
  } else {
  src = src_;
  if (src.dtype() != dst_.dtype()) {
  // In case of dtype change, perform conversion on source device
  src = src.to(dst_.dtype());
  }
+ size = src.nbytes();
  }
 
  const void* host_src = src.storage().data();
- // Get the actual size of a View (takes into account the storage offset)
- // For View tensors, the storage offset can be bigger than what's being reported by nbytes
- uint64_t size = at::detail::computeStorageNbytesContiguous(src.sizes(), src.element_size(), src.storage_offset());
 
  NSUInteger sourceOffset = 0;
  @autoreleasepool {