[clang] [llvm] [Transforms][Utils][PromoteMem2Reg] Propagate nnan flag on par with the nsz flag (PR #114271)

[Nikita Popov via cfe-commits]

nikic wrote:

I do think this change still makes sense, especially from a consistency point of view. If SROA sets one of the value-based FMF flags (nsz) then it stands to reason that it should also set the other two (nnan and ninf). Unless there is some reason why nsz would be more problematic than nnan/ninf in this context (it does have substantially different semantics).

https://github.com/llvm/llvm-project/pull/114271