[llvm] [GlobalISel]: G_UNMERGE_VALUES for vectors with different element sizes (PR #133335)

[Jay Foad via llvm-commits]

jayfoad wrote:

> But afaics, the MachineVerifier cannot catch invalid instructions that are created during legalization before they are being handled themselves in the same pass.

OK, but that's a technicality. The instructions are still invalid and should not have been created, so the correct fix is to not create them in the first place.

https://github.com/llvm/llvm-project/pull/133335