[llvm] [RISCV] Ensure the valid vtype during copyPhysReg (PR #118252)

[Piyou Chen via llvm-commits]

BeMg wrote:

This patch works incorrectly when inserting the vsetivli instruction. The VSETVLInfo is necessary. Without this information, the previous vtype status will be broken. I'm unsure whether we should reuse the analysis from the insert-vsetvl pass here or create a standalone pass to emit the valid vtype for whole vector register move.

https://github.com/llvm/llvm-project/pull/118252