[llvm] [MachineOutliner] Leaf Descendants (PR #90275)

[Xuan Zhang via llvm-commits]

================
@@ -105,6 +114,68 @@ void SuffixTree::setSuffixIndices() {
   }
 }
 
+void SuffixTree::setLeafNodes() {
+  // A stack that keeps track of nodes to visit for post-order DFS traversal.
+  std::stack<SuffixTreeNode *> ToVisit;
----------------
xuanzh-meta wrote:

No real advantages of using `std::stack`, I will update the `std::stack` to `SmallVector`.

https://github.com/llvm/llvm-project/pull/90275