llvm-project

64fe3236 - [llvm] Migrate away from ArrayRef(std::nullopt) (NFC) (#144967)

[llvm] Migrate away from ArrayRef(std::nullopt) (NFC) (#144967) ArrayRef has a constructor that accepts std::nullopt. This constructor dates back to the days when we still had llvm::Optional. Since the use of std::nullopt outside the context of std::optional is kind of abuse and not intuitive to new comers, I would like to move away from the constructor and eventually remove it. This patch takes care of the llvm side of the migration.