pytorch

1f61c39a - Revert "Support NCCL Premul Sum (#81272)"

Revert "Support NCCL Premul Sum (#81272)" This reverts commit 432c508e71111f9d5382322e0e6b1bc1c66bf0ec. Reverted https://github.com/pytorch/pytorch/pull/81272 on behalf of https://github.com/weiwangmeta due to breaking internal builds