message: accept empty interval in binary_search()
diff: @@ -154,10 +154,11 @@ Index binary_search(scalar_t<Index> start_,
  scalar_t<Index> end_,
  const Predicate &pred,
  mask_t<Index> active = true) {
  -
  - scalar_t<Index> iterations = log2i(end_ - start_) + 1;
  Index start(start_), end(end_);
  + scalar_t<Index> iterations = (start_ < end_) ?
  + (log2i(end_ - start_) + 1) : 0;
  +
  for (size_t i = 0; i < iterations; ++i) {
  active &= end > start;
  Index middle = sr<1>(start + end);
  