[llvm] [GlobalISel][TableGen] MIR Pattern Variadics (PR #100563)

[Pierre van Houtryve via llvm-commits]

Pierre-vh wrote:

For awareness: This is pretty much a WIP, it's complete as-is and could land - hence why no WIP tag - but suggestions are highly welcome. If you feel like this isn't usable without some limitations being lifted (such as having variadic defs), or some feature added (like extracting individual operands in the pack), let me know and give me your thoughts/syntax ideas/etc.

I can make a forum post if the discussion really picks up too

https://github.com/llvm/llvm-project/pull/100563