[llvm] [AMDGPU] Fix undefined scc register in successor block of SI_KILL terminators (PR #134718)

[Matt Arsenault via llvm-commits]

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@@ -4513,7 +4513,7 @@ Register SITargetLowering::getRegisterByName(const char *RegName, LLT VT,
 MachineBasicBlock *
 SITargetLowering::splitKillBlock(MachineInstr &MI,
                                  MachineBasicBlock *BB) const {
-  MachineBasicBlock *SplitBB = BB->splitAt(MI, false /*UpdateLiveIns*/);
+  MachineBasicBlock *SplitBB = BB->splitAt(MI, true /*UpdateLiveIns*/);
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arsenm wrote:

```suggestion
  MachineBasicBlock *SplitBB = BB->splitAt(MI, /*UpdateLiveIns=*/true);
```

https://github.com/llvm/llvm-project/pull/134718