[llvm] [AMDGPU] narrow only on store to pow of 2 mem location (PR #150093)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> But the real question is: are we actually going to support arbitrary integer sizes?

There is no question, yes. It is part of the IR and must be handled 



https://github.com/llvm/llvm-project/pull/150093