9a7e307b64
This adds a test that exercises the part of scalarizeBinOpOrCmp that produces immediate UB as described in https://github.com/llvm/llvm-project/pull/138095#discussion_r2070133432, but is fortunately currently folded into a correct transform. I also noticed a bunch of immediate UB in some of the existing tests so this also cleans them up. They should still all be scalarized though.