[llvm] [Utils] Fix incorrect LCSSA PHI nodes when splitting critical edges with MergeIdenticalEdges (PR #131744)

[Nikita Popov via llvm-commits]

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@@ -217,6 +219,9 @@ llvm::SplitKnownCriticalEdge(Instruction *TI, unsigned SuccNum,
 
       // We found another edge to DestBB, go to NewBB instead.
       TI->setSuccessor(i, NewBB);
+
+      // Record the number of splitted identical edges to DestBB.
----------------
nikic wrote:

```suggestion
      // Record the number of split identical edges to DestBB.
```

https://github.com/llvm/llvm-project/pull/131744