[llvm] [mlir] [NFC][mlir][NVVM] Move op descriptions to NVVMOpsDoc.td (PR #225090)

[Rajat Bajpai via llvm-commits]

rajatbajpai wrote:

> Can you expand on why?

Sure. My reasoning for moving ops with large descriptions to a separate Doc.td file is that these descriptions make the op interface harder to read.

> Not only is this unusual, but also having the documentation separate makes it less likely that it will be kept in sync and updated when the operation evolves.

I agree that stale documentation is always a possibility, even with inline descriptions. We can address this during code review.

Separate documentation also has another benefit. TMA family (and others) ops share some functionality, but we currently duplicate the corresponding descriptions across all the ops. Ideally, we should define the common description once and reuse it across the ops so that it is easier to update and maintain.

Doing this requires TD concatenation. If we add that concatenation to the op TD file, I believe it would make the file more cluttered. IMHO, if we need this structure, it is better to keep it in a separate file.

https://github.com/llvm/llvm-project/pull/225090