They are not commonly classified as philosophers. However: Logic is often classed as a branch of philosophy, and that covers the Gödel work, and more, mentione

They are not commonly classified as philosophers. However: Logic is often classed as a branch of philosophy, and that covers the Gödel work, and more, mentioned. There is plenty of writing, much of it by real philosophers, about how foundational work in QM, for example, did have profound philosophical implications and did influence the development of philosophy. The physicists who invented QM had many discussions about its philosophical implications, and these discussions have been studied by philosophers and influence philosophy. The division separating “philosophy” from mathematics, physics, and even logic is recent and arbitrary. And finally, if an academic philosopher finds math too hard, that is not a good reason to disqualify it from being considered “philosophy”.