This change appears to introduce complications when trying to do a full loop unroll that is exhibited here: https://github.com/llvm/llvm-project/actions/runs/24577221310/job/71865579618. This results in invalid DXIL as the unreachable branch is not correctly cleaned up. Initial leads look like this is because the instructions with convergence control tokens are still being used for analysis when they are within an unreachable branch. Reverts llvm/llvm-project#188792