func multi(f *Func) {
	cse(f)
	dse(f)
	deadcode(f)
}
func BenchmarkMultiPass(b *testing.B)      { benchFnPass(b, multi, blockCount, genFunction) }
func BenchmarkMultiPassBlock(b *testing.B) { benchFnBlock(b, multi, genFunction) }

// benchFnPass runs passFunc b.N times across a single function.
func benchFnPass(b *testing.B, fn passFunc, size int, bg blockGen) {
	b.ReportAllocs()