No Branch 

for (auto i = 0u; i < arr.size(); ++i) {
  if (arr[i] > 128)
    sum += arr[i];
}

for (auto i = 0u; i < arr.size(); ++i) {
  sum += arr[i] * (arr[i] > 128);
}

* The benchmark is run under Apple Macbook Air M2.

* For the full benchmark code, please refer here.