[flang] [llvm] [Flang][OpenMP][Sema] Adding parsing and semantic support for scan directive. (PR #102792)

[Sergio Afonso via llvm-commits]

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@@ -198,6 +198,10 @@ class DirectiveStructureChecker : public virtual BaseChecker {
     ClauseMapTy clauseInfo;
     std::list<C> actualClauses;
     std::list<C> crtGroup;
+    std::set<std::string> usedInScanDirective;
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skatrak wrote:

I think `std::set<const Symbol *>` would be a better data type choice for this. Another issue is that this structure is used for both OpenMP and OpenACC, so I think this should be moved to the `OmpStructureChecker` subclass (in check-omp-structure.h). Same issue with the `reductionMod` below.

https://github.com/llvm/llvm-project/pull/102792