[clang] [CIR] Fix warnings related to unused variables in release builds (PR #151412)

[Andy Kaylor via cfe-commits]

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@@ -216,7 +216,7 @@ void CIRGenFunction::emitAndUpdateRetAlloca(QualType type, mlir::Location loc,
 void CIRGenFunction::declare(mlir::Value addrVal, const Decl *var, QualType ty,
                              mlir::Location loc, CharUnits alignment,
                              bool isParam) {
-  const auto *namedVar = dyn_cast_or_null<NamedDecl>(var);
+  [[maybe_unused]] const auto *namedVar = dyn_cast_or_null<NamedDecl>(var);
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andykaylor wrote:

The assert can be rewritten to eliminate this one. I didn't notice that until now.

https://github.com/llvm/llvm-project/pull/151412