There's no reason to run the optimisation discovery at compile time. Anything that changes the structure can be run to change the source ahead of time. Anything that doesn't can be generalised into a typical optimisation step in the existing compiler pipeline. Same applies to Souper for example - you really don't want everyone to run it.
That too. But mainly for transforming the source ahead of time to be more optional. If there's some low level, local optimisation, that can be found once and implemented as a stable, repeatable idea in the compiler code instead.
