[llvm] [Verifier][AMDGPU] No store to const addrspace (PR #109181)

[Matt Arsenault via llvm-commits]

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

This must be UB, and not a verifier error. For example, we allow constant->flat casts. We do not want to have to consider the address spaces involved when folding something like store (addrspacecast ptr addrspace(4) %val to ptr)

https://github.com/llvm/llvm-project/pull/109181