[clang] [Clang] Add __builtin_get_counted_by builtin (PR #102549)

[via cfe-commits]

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@@ -222,6 +222,49 @@ bool Expr::isFlexibleArrayMemberLike(
                                          IgnoreTemplateOrMacroSubstitution);
 }
 
+namespace {
+
+/// MemberExprVisitor - Find the MemberExpr through all of the casts, array
+/// subscripts, and unary ops. This intentionally avoids all of them because
+/// we're interested only in the MemberExpr to check if it's a flexible array
+/// member.
+class MemberExprVisitor
+    : public ConstStmtVisitor<MemberExprVisitor, const Expr *> {
+public:
+  //===--------------------------------------------------------------------===//
+  //                            Visitor Methods
+  //===--------------------------------------------------------------------===//
+
+  const Expr *Visit(const Expr *E) {
+    return ConstStmtVisitor<MemberExprVisitor, const Expr *>::Visit(E);
+  }
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Sirraide wrote:

```suggestion
```
I don’t think this needs to exist, or am I missing something?

https://github.com/llvm/llvm-project/pull/102549