[llvm] [RFC][TableGen] Require DAG argument for complex operands in InstAlias (PR #136411)

[Paul Walker via llvm-commits]

https://github.com/paulwalker-arm approved this pull request.

I've raised a couple of minor things but otherwise this looks good to me. Personally I don't mind the extra verbosity because it makes it easier to interpret the operands whilst also adding confidence the aliases map to the desired instruction class. It might even encourage more expressive naming for the complex patterns.

With the said, I'm not sure how authoritative I can be in accepting the PR so please do allow time for others to raise their objections.

https://github.com/llvm/llvm-project/pull/136411