[llvm] [IPO] Added attributor for identifying invariant loads (PR #141800)

[Shilei Tian via llvm-commits]

shiltian wrote:

> > Yeah, that's what I meant. `TTI::isGlobalConstantsAddressSpace(unsigned)` if such a thing doesn't already exist
> 
> I don't think such a thing already exists, but I feel like adding such support would make more sense as a separate PR.

Ideally yes, but in practice maybe challenging. I've tried to add stuff about address spaces into some common files several times in the past but got a lot of push back. Almost none of those effort succeeded. The essential question is the definition. For this particular case, I'd imagine the challenge is how to define a "global constant" address space? What is its characteristic?

https://github.com/llvm/llvm-project/pull/141800