[llvm] [CodeGen] Update for scalable MemoryType in MMO (PR #70452)

[David Green via llvm-commits]

davemgreen wrote:

I've been having a look into making it a LocationSize. The size internally is stored in the size of a LLT, so it is only the input and output from the MMO that would handle LocationSize. (And afterPointer would not be supported, but that is probably fine).

I've had a go at making it use LocationSize. There are obviously a lot more changes, as it can no longer rely upon the implicit conversions from TypeSize->unsigned or from UnknownSize->unsigned. Hopefully I handled them all correctly, some places make the assumption that values cannot be Unknown, or handle it strangely it they do.

https://github.com/llvm/llvm-project/pull/70452