[llvm] [TableGen][DecoderEmitter] Add option to emit type-specialized `decodeToMCInst` (PR #146593)

[Craig Topper via llvm-commits]

topperc wrote:

> Actually, `git grep CppTypeName` shows a lot of hits in LLVM, so there is precedent on LLVM side as well.

Aren't those all part of the description for a searchable table? They're contained in the description of the table along with the other table properties. So it's at least connected and not some extra information off to the side somewhere. I think this goes back to my previous suggestion of it being part of the instruction class.

I also don't like it being opt-in. Ideally we wouldn't have two different ways of creating decoders that we need to maintain. It would be nice if out of tree developers could get benefits without needing to stumble onto this new feature.

I'll think more about this over the weekend.

https://github.com/llvm/llvm-project/pull/146593