[PATCH] D38599: Remove warnings for dynamic_cast fallback.

[Ryan Prichard via Phabricator via cfe-commits]

rprichard added a comment.

Some relevant code links:

- https://github.com/llvm-mirror/clang/blob/8c9bf999aa40ab6077b958b5edcf587b9d76ce24/lib/CodeGen/ItaniumCXXABI.cpp#L359 ==> iOS64CXXABI overrides shouldRTTIBeUnique to return false.
- https://github.com/llvm-mirror/libcxx/blob/ca79c159d8bfbe190a6cbfce74eb2d050697d8b9/include/typeinfo#L176 ==> libc++ type_info::operator== uses string comparison, but only if _LIBCPP_NONUNIQUE_RTTI_BIT has been OR'ed into the __type_name pointers of both type_info objects
- https://github.com/llvm-mirror/libcxx/blob/ca79c159d8bfbe190a6cbfce74eb2d050697d8b9/include/__config#L879 ==> use the highest bit for ARM64 iOS


Repository:
  rL LLVM

https://reviews.llvm.org/D38599