Clarify logic in `ir_emitter` (#51299)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/51299
Test Plan: Imported from OSS
Reviewed By: gmagogsfm
Differential Revision: D26131245
Pulled By: ansley
fbshipit-source-id: ecd69275214775804f5aa92f9b4c0b19be19b596
