[MaxGabriel]

To expand on this, it also lets them target new CPU architectures without having developers recompile code for that architecture. This lets them make incremental improvements (eg armv7), but would also let them use their own CPU architecture should they move away from Intel/ARM.

As an example here’s Chris Lattner tweeting about that use case:

https://twitter.com/clattner_llvm/status/1091186386634326017...

[saagarjha]

> but would also let them use their own CPU architecture should they move away from Intel/ARM

Only if their new architecture looked a lot like Intel/ARM. Bitcode can’t paper over all architectural differences.

[pjmlp]

Regular bitcode cannot do it. However Apple has naturally customized it for their own purposes.

Not everything that Apple does lands on upstream.