[llvm] [llvm][Tablegen][llvm-tblgen] Added keyword #undef to llvm-tblgen (PR #69135)

[Mehdi Amini via llvm-commits]

joker-eph wrote:

> I am so sorry, I don't quite understand what you mean. So is it still necessary to add the ‘#undef’ keyword?

I actually suspect that what you're trying to enable would be exactly something I don't quite see as desirable right now.
I can be wrong though, but the need for doing this hasn't arised in all the TableGen use I've seen, so I'm not able to weigh our conflicting goals against each other right now. 
I read your Discourse thread, but don't find this very motivated right now: do you have real world use-cases that could be improved by this?

https://github.com/llvm/llvm-project/pull/69135