Port lcm to structured (#57628)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/57628
Test Plan: Imported from OSS
Reviewed By: VitalyFedyunin
Differential Revision: D28224833
Pulled By: ezyang
fbshipit-source-id: 17ba9ea419a9fab5dcbdaefbe6d330e2e74c1e1f
