Performance of modulo or bit operation in golang for checking even?

even_test.go

func BenchmarkCheckEven(b *testing.B) {
	nums := make([]uint64, 10000)
	for i := 0; i < len(nums); i++ {
		bytes := make([]byte, 8)
		_, err := rand.Read(bytes)
		require.NoError(b, err)
		val := binary.BigEndian.Uint64(bytes)
		nums[i] = val
	}

	results := make([]bool, 10000)

	b.Run("modulo", func(b *testing.B) {
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			for i := 0; i < len(nums); i++ {
				if nums[i]%2 == 0 {
					results[i] = true
				}
			}
		}
	})

	b.Run("bitop", func(b *testing.B) {
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			for i := 0; i < len(nums); i++ {
				if nums[i]&1 == 0 {
					results[i] = true
				}
			}
		}
	})
}


It turns out they are the same, since they compile to the exactly the same three operations in assembly.

MOVQ	(SI)(R8*8), R9
BTL	$0, R9
JCS	126