&gt; I don&#x27;t see why a new compiler would be necessary. It&#x27;s unlikely they&#x27;d completely throw out the whole ARM ISA and replace it with something completely different in one go. More likely, they&#x27;ll gradually add new instructions and mutate the characteristics of existing instructions over time<p>Well this is exactly the point.  They cannot do this the license will not permit them to alter the architecture it&#x27;s all or nothing (indeed if the new ISA was too ARM like the lawyers would be sure to come knocking).<p>I&#x27;m sure the could reuse quite a lot of compiler technology but the entire point of the article is by doing clean slate ISA design you can do something radical and get gains.  Whether this is true is unclear, but it would require some serious work on the compiler.<p>Producing their own conventional ISA would seem to be pointless as it wouldn&#x27;t give them anything vs ARM (or indeed x86).