[llvm] [FuncComp] Compare MDNodes in cmpMetadata using cmpMDNode. (PR #128878)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

I'm somewhat unhappy about doing deep metadata comparison. IMHO, we should not be comparing instruction metadata at all, and instead doing a combineMetadata run to combine metadata between the merged functions. This results in more merging opportunities, while also avoiding the need to implement complex comparison logic.

We *do* need to compare metadata arguments to calls, but I think the inputs that are used there are a lot more limited -- I think it's pretty much only MDStrings?

https://github.com/llvm/llvm-project/pull/128878