[llvm] [AMDGPU][GFX12.5] Add support for emitting memory operations with nv bit set (PR #179413)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm requested changes to this pull request.

Probably shouldn't have metadata that's defined as "set this bit that sometimes exists on the target." How is this supposed to interact with MMRAs, nontemporal, and the other nontemporal replacement proposals floating around? Do you even really need this? For the spill marking you can just hack the MMO flag without the metadata dependence 

https://github.com/llvm/llvm-project/pull/179413