[clang] [llvm] [CHERI] Allow @llvm.returnaddress to return a pointer in any address space. (PR #188464)

[Owen Anderson via cfe-commits]

resistor wrote:

> Thanks. Do we have others like this still? I forget which have been upstreamed (or reinvented by others) over the years.

We have similar changes for `@llvm.read.register`, `@llvm.write.register`, `@llvm.read.volatile.register`, and `@llvm.stackprotector`.

It's my intent to get to those as well, but this one was the most invasive and felt like it deserved its own PR.

https://github.com/llvm/llvm-project/pull/188464