This PR does the following things:
- Code refactoring on Load and Store op codegen, rewrite with same logic
and share much code
- Support the vectorized load/store
* [BACKEND] two minor bugfix on StoreOpLowering and kernel launch & support optional other in LoadOpLowering
* Clean code
Co-authored-by: goostavz <gzhu@nvidia.com>
Co-authored-by: Yan Chunwei <yanchunwei@outlook.com>
