Compound subjects and compound sentences
[1] John and Harry sang well.
[2] John sang well and Harry sang well.
A lower-level distributive coordination like that in [1] can be expanded into a logically equivalent main-clause one, as in [2].
But that doesn't mean that [1] is a compound sentence; it's not. It's a simple sentence with one subject, "John and Harry", and the single predicate "sang well".