[llvm] [PGO] Supporting code for always instrumenting loop entries (PR #116789)

[Christian Ulmann via llvm-commits]

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@@ -154,6 +159,9 @@ template <class Edge, class BBInfo> class CFGMST {
           }
           if (BPI != nullptr)
             Weight = BPI->getEdgeProbability(&BB, TargetBB).scale(scaleFactor);
+          if (InstrumentLoopEntries && LI != nullptr &&
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Dinistro wrote:

Nit: Maybe explain in a small comment what is happening here.

https://github.com/llvm/llvm-project/pull/116789