[llvm] [RISCV] Shrink uses of coalesced vsetvlis (PR #98286)

[Philip Reames via llvm-commits]

https://github.com/preames commented:

I realized when taking a deeper look that you're duplicating functionality here.  This same case is supposed to be handled in the "if (DefReg.isVirtual() && LIS) {" above.  I think what happens is that you've got an order of operations bug.  You need to *actually* modify the instruction first, then perform all of the LIS update.  (That is, move that block done to just before the OldVReg update, and maybe move the setDesc call up.  

https://github.com/llvm/llvm-project/pull/98286