s.values[id].uses = r
	if r.next != nil && dist > r.next.dist {
		s.f.Fatalf("uses added in wrong order")
	}
}

// advanceUses advances the uses of v's args from the state before v to the state after v.
// Any values which have no more uses are deallocated from registers.
func (s *regAllocState) advanceUses(v *Value) {
	for _, a := range v.Args {
		if !s.values[a.ID].needReg {
			continue
		}
		ai := &s.values[a.ID]