Function upper_bound

tensorflow/core/util/gpu_kernel_helper.h:285–302

namespace gpu_helper {
template <typename T, typename OutType = int32>
__device__ OutType upper_bound(const T* first, OutType count, T val) {
  const T* orig = first;
  const T* it = nullptr;
  OutType step = 0;
  while (count > 0) {
    it = first;
    step = count / 2;
    it += step;
    if (!(val < *it)) {
      first = ++it;
      count -= step + 1;
    } else {
      count = step;
    }
  }

  return first - orig;
}

template <typename T, typename OutType = int32>
__device__ OutType lower_bound(const T* first, OutType count, T val) {