[llvm] [Support][NFC] Use single predecessor array in DomTreeConstr (PR #207535)

[Alexis Engelke via llvm-commits]

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@@ -78,6 +78,10 @@ template <typename DomTreeT> struct SemiNCAInfo {
                      DenseMap<NodePtr, InfoRec>>
       NodeInfos;
 
+  /// Reverse children of nodes; pairs of (DFSNum (predecessor), next-or-zero);
+  /// forms a linked list in this vector; first entry is sentinel.
+  SmallVector<std::pair<unsigned, unsigned>> ReverseChildren = {{0, 0}};
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aengelke wrote:

Changed.

https://github.com/llvm/llvm-project/pull/207535