I can&#x27;t see this as a definitive sign that Apple are going to introduce a new ISA. Instead, this gives them flexibility. They can switch ISAs (e.g. to a new ARM revision, it doesn&#x27;t have to be an Apple-specific one though) without authors having to recompile their code for all platforms. It also allows Apple to support multiple ISAs without code bloat - the app store can download the correct binary to your phone, just like they now can send only the correct size images.<p>I don&#x27;t know how abstract the LLVM IR is - can you take IR and compile it to two wildly different ISAs, (say) x86 and ARM, and get full optimisation on both?  Or is it more limited, e.g. allowing you to compile to ARM version x and ARM version y (e.g. if version &#x27;y&#x27; supports some new SIMD instructions).