How can a user tell whether the new compiler is being used?

[CampGareth]

To use the new compiler a user sets a variable in their reco.yml and assumes that value will be checked. How can they tell if the new compiler was actually used as part of a build, sim, graph etc?

Builds: The logs could indicate which compiler was used
Sims: Could also use logs
Graphs: ??? There are no logs for a graph as far as I know