This has been stated before: LLVM Bitcode is architecture specific. It&#x27;s dependent on the architectures ABI and can contain inline assembly. There are LLVM targets with corresponding ABIs that are nonspecific to architectures like PNaCL but Apple is not using them<p>Things Apple can do with bitcode:
Produce binaries optimized for different ARM processors. Reoptimize with new versions of LLVM as soon as they are available. Use a big database of LLVM IR to tweak optimizations. Keep some optimizations secret and not even publish binaries doing them.<p>The biggest argument IMO that speaks against an Apple ISA is that they would have to rewrite tons of hand tuned assembly code.