The bypass compile function in evergreen.yml is really valuable and saves a lot of time for patch builds which do not have any artifacts that require a compile. However the compile will happen anyway when the compile for the base commit has not completed. It could be that on this build variant a compile will never occur (since it will never be scheduled), but there are several patch builds which use that base commit on that build varaint. It should be possible to determine if any the patch builds, which have the completed compile artifacts, have no source changes as well. In this case those artifacts could be used to bypass compile.