[llvm] [RISCV][MI] Support partial spill/reload for vector registers (PR #105661)

[Luke Lau via llvm-commits]

https://github.com/lukel97 commented:

Just an idea, but in #107446 there are subregisters added for GPR which reduces the spill size. Can we do the same for VR and add subregisters for fractional LMULs? Would that help with the spills? 

https://github.com/llvm/llvm-project/pull/105661