Avoid clone for sparse tensors during accumulation of grads. (#33427)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/33427
This PR is an attempt to avoid clone for sparse tensors similar to how
we avoid clone for dense tensors currently.
As per my understanding even if the 'indices' and 'values' of a sparse tensor
are non-continguous, operations like 'add' are still supported. As a result,
the major change in this PR is to use create a shallow copy instead of clone()
for sparse tensors.
ghstack-source-id: 99838375
Test Plan: waitforbuildbot
Differential Revision: D19926698
fbshipit-source-id: b5a3f36c2aa273e17f8b7a9f09c1ea00e7478109
