On Fri, 31 Jan 2025, Abhishek Kaushik wrote:
The current while loop in std::reduce and related functions is hard to vectorize because the loop control variable is hard to detect in icx.`while ((__last - __first) >= 4)` Changing the loop header to a for loop following the OpenMP canonical form allows easy vectorization, resulting in improved performance. `for (; __first <= __last - 4; __first += 4)`
Is that always legal? If the sequence has size 1, is __last - 4 well defined?
-- Marc Glisse
