f.Names = append(f.Names, newNames...)
}

func maybeAppend(f *Func, ss []*LocalSlot, s *LocalSlot) []*LocalSlot {
	if _, ok := f.NamedValues[*s]; !ok {
		f.NamedValues[*s] = nil
		return append(ss, s)
	}
	return ss
}

func maybeAppend2(f *Func, ss []*LocalSlot, s1, s2 *LocalSlot) []*LocalSlot {
	return maybeAppend(f, maybeAppend(f, ss, s1), s2)
}

func decomposeBuiltInPhi(v *Value) {