It depends. If the code flow is uniform for the warp, only side of the branch needs to be evaluated. But you could still end up with pessimistic register alloca

It depends. If the code flow is uniform for the warp, only side of the branch needs to be evaluated. But you could still end up with pessimistic register allocation because the compiler can’t know it is uniform. It’s sometimes weirdly hard to reason about how exactly code will end up executing on the GPU.