[llvm] [SandboxIR][Region] Auxiliary vector metadata now requires a region (PR #137443)

[Jorge Gorbe Moya via llvm-commits]

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@@ -115,7 +115,7 @@ class Region {
   Context::CallbackID EraseInstCB;
 
   /// Adds I to the set.
-  void add(Instruction *I);
+  void add(Instruction *I, bool TrackScore = true);
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slackito wrote:

Please add a comment explaining what's the intended use case for passing `false` here. Actually, if it doesn't make sense outside of `setAux` and `createRegionsFromMD` we could even add a separate overload (instead of a default argument) and make the 2-argument overload private. WDYT?

https://github.com/llvm/llvm-project/pull/137443