Function moves 

pub fn moves(
    func: &mut Func,
    insts: &BranchInsts,
    flags: &FlagInsts,
    machine: &MachineInsts,
    names: &mut Interner,
    fusable: &HashMap<Inst, usize>,
) -> usize

Turns every comparison fusable found, and the selects reading its byte, into the comparison keeping nothing and the moves on its condition.

Gives back how many comparisons it did that for, which the tests read and nothing else does.