[NNC] Support vectorization of reductions (#47924)
Summary:
Add support for ReduceOp in the Vectorizer, which allows vectorization of reductions. Only non-reduce axes can be vectorized currently, we'd need either automatically pulling out the RHS of reductions (better as a separate transform, I think) or special handling of vector reduce in the LLVM codegen (tricky, maybe not useful?) to make vectorizing reduce axes work.
There was a disabled LLVM test for this case which I reenabled with a bit of massaging, and added a few more.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47924
Reviewed By: bertmaher
Differential Revision: D24963464
Pulled By: nickgg
fbshipit-source-id: 91d91e9e2696555ab5690b154984b1ce48359d51
