[llvm] Port NVPTXTargetLowering::LowerCONCAT_VECTORS to llvm/lib/CodeGen/SelectionDAG (PR #120030)

[Ethan Kaji via llvm-commits]

Esan5 wrote:

I did see this, is it ok to just overwrite test cases like this? I'm worried I may break something I don't understand.


https://github.com/llvm/llvm-project/pull/120030