[llvm] [IR] Verify oracle functions are only used by llvm.speculative.load. (PR #226669)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 commented:

Maybe a little bit premature, but I'm wondering if we want a first class attribute that has the same effect but is maybe slightly more generic? I was thinking an attribute like `ghost` would work nicely here. We could definite at as being semantically important in IR but shouldn't generate any code. I don't actually have any further uses in mind though...

Either way, I think deleting oracle functions during ISel is the best course of action. Trying to do it earlier introduces IR "dialects" which would be kind of annoying.

https://github.com/llvm/llvm-project/pull/226669