[llvm] Reapply "[MemProf] Streamline and avoid unnecessary context id duplication (#107918)" (PR #110036)

[Teresa Johnson via llvm-commits]

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@@ -1379,7 +1379,15 @@ void CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::
   DenseSet<uint32_t> LastNodeContextIds = LastNode->getContextIds();
   assert(!LastNodeContextIds.empty());
 
+#ifndef NDEBUG
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teresajohnson wrote:

yeah, I was concerned that I would get compiler warnings about unused variables, since PrevIterCreatedNode is only read by an assert, but I didn't seem to.

https://github.com/llvm/llvm-project/pull/110036