[PyTorch] TensorImpl::is_non_overlapping_and_dense_ should default to…

… true (#48625)

Summary:
Pull Request resolved: #48625

The default TensorImpl is contiguous. Therefore, it is non-overlapping and dense per refresh_contiguous().
ghstack-source-id: 118035410

Test Plan: CI

Reviewed By: ezyang

Differential Revision: D25232196

fbshipit-source-id: 1968d9ed444f2ad5414a78d0b11e5d3030e3109d

aten/src/ATen/SparseTensorImpl.cpp

@@ -46,6 +46,8 @@ SparseTensorImpl::SparseTensorImpl(at::DispatchKeySet key_set, const caffe2::Typ
   AT_ASSERT(values_.sizes() == IntArrayRef({0}));
   AT_ASSERT(values_.device() == indices_.device());
   AT_ASSERT(values_.device() == device());
+
+  is_non_overlapping_and_dense_ = false;
 }
 
 IntArrayRef SparseTensorImpl::strides() const {

c10/core/TensorImpl.h

@@ -1706,7 +1706,7 @@ struct C10_API TensorImpl : public c10::intrusive_ptr_target {
     is_channels_last_contiguous_ = false;
     is_channels_last_3d_ = false;
     is_channels_last_3d_contiguous_ = false;
-    is_non_overlapping_and_dense_ = false;
+    is_non_overlapping_and_dense_ = true;
     is_wrapped_number_ = false;
     allow_tensor_metadata_change_ = true;
     reserved_ = false;