[llvm] [RISCV][Peephole] Clear kill flags for registers after fold VMV (PR #138847)

[Luke Lau via llvm-commits]

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@@ -655,6 +656,7 @@ bool RISCVVectorPeephole::foldVMV_V_V(MachineInstr &MI) {
   MRI->replaceRegWith(MI.getOperand(0).getReg(), Src->getOperand(0).getReg());
   MI.eraseFromParent();
 
+  MRI->clearKillFlags(MI.getOperand(2).getReg());
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lukel97 wrote:

I think MI will be deleted by this point, we should probably use Src instead

```suggestion
  MRI->replaceRegWith(MI.getOperand(0).getReg(), Src->getOperand(0).getReg());
  MRI->clearKillFlags(Src->getOperand(0).getReg());
  MI.eraseFromParent();
  
```

https://github.com/llvm/llvm-project/pull/138847