Decoding instructions is ugly but a solved problem. As for scheduling instructions optimally, Itanium tried this, but they never achieved a “sufficiently smart

Decoding instructions is ugly but a solved problem. As for scheduling instructions optimally, Itanium tried this, but they never achieved a “sufficiently smart compiler” to make full use of the microarchitectural pipelines and registers (and cache?). Even if they had, that code might make poor use of future CPUs, because more pipelines will be available for more instructions or retire some of them faster than expected.