[llvm] [DebugInfo][InstCombine] When replacing bswap idiom, add DebugLoc to new insts (PR #114231)

[Nikita Popov via llvm-commits]

nikic wrote:

FWIW, I think that trying to use a merged location rather than the location of the last instruction in InstCombine would be completely impractical. Taking the last instruction can be done automatically, while a merged location would require each individual fold to track which instructions "contribute" towards it (a notion that is not going to be particularly well-defined for many folds anyway).

https://github.com/llvm/llvm-project/pull/114231