[clang] [OpenMP] Fix infinite loop on recursive initializers (PR #126269)

[Alexey Bataev via cfe-commits]

================
@@ -22819,8 +22819,12 @@ class GlobalDeclRefChecker final : public StmtVisitor<GlobalDeclRefChecker> {
   void declareTargetInitializer(Decl *TD) {
     A = TD->getAttr<OMPDeclareTargetDeclAttr>();
     DeclVector.push_back(cast<VarDecl>(TD));
+    llvm::DenseSet<Decl *> Visited;
----------------
alexey-bataev wrote:

Better to use SmallDenseSet

https://github.com/llvm/llvm-project/pull/126269