[llvm] [CodeLayout][NFC] Using MergedVector to avoid extra vector allocations (PR #68724)

[Rahman Lavaee via llvm-commits]

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@@ -507,43 +507,56 @@ struct MergedChain {
 
   const NodeT *getFirstNode() const { return *Begin1; }
 
+  bool empty() const { return Begin1 == End1; }
+
+  void append(ObjIter Begin, ObjIter End) {
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rlavaee wrote:

This function is introduced just because we're reusing this struct for Jumps (which can only contain up to 2 ranges of jumps).

https://github.com/llvm/llvm-project/pull/68724