Decomposition for adaptive_avg_pool2d (#84062)
This was already implemented as a lowering in https://github.com/pytorch/torchdynamo/pull/962. I'm putting the idea up here ~(I haven't even run this code, so it surely has *many* issues, but I reckon the general idea should hopefully be alright).~ The tests now pass and I corrected the issues that the first implementation had.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/84062
Approved by: https://github.com/jansel
