[clang] [CIR] Unblock simple C++ structure support (PR #138368)

[Bruno Cardoso Lopes via cfe-commits]

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@@ -365,10 +365,15 @@ mlir::Attribute ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &d) {
   if (!d.hasLocalStorage()) {
     QualType ty = cgm.getASTContext().getBaseElementType(d.getType());
     if (ty->isRecordType())
-      if (d.getInit() && isa<CXXConstructExpr>(d.getInit())) {
-        cgm.errorNYI(d.getInit()->getBeginLoc(),
-                     "tryEmitPrivateForVarInit CXXConstructExpr");
-        return {};
+      if (const CXXConstructExpr *e =
+              dyn_cast_or_null<CXXConstructExpr>(d.getInit())) {
+        const CXXConstructorDecl *cd = e->getConstructor();
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bcardosolopes wrote:

We have been careful not to elide things too early since it might hurt static analysis - this is a big pain point and request from the static analysis community (as clang really early get rid of these). The idea is to represent them in a way that during LoweringPrepare we can either elide them out or apply specific lowering heuristics (e.g. when deciding the best way to initialize large set of constant datas).

https://github.com/llvm/llvm-project/pull/138368