Index: clang/lib/Driver/ToolChains/OpenBSD.h
--- clang/lib/Driver/ToolChains/OpenBSD.h.orig
+++ clang/lib/Driver/ToolChains/OpenBSD.h
@@ -79,6 +79,11 @@ class LLVM_LIBRARY_VISIBILITY OpenBSD : public Generic
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
 
+  bool IsAArch64OutlineAtomicsDefault(
+      const llvm::opt::ArgList &Args) const override {
+    return true;
+  }
+
   std::string getCompilerRT(const llvm::opt::ArgList &Args, StringRef Component,
                             FileType Type = ToolChain::FT_Static,
                             bool IsFortran = false) const override;
