3 ms·

pbsd investigated above[1] and found that the problem was the use of signed chars. [1]: https://news.ycombinator.com/item?id=7737582 https://news.ycombinator.c

by dbaupp 12y ago

pbsd investigated above[1] and found that the problem was the use of signed chars. [1]: https://news.ycombinator.com/item?id=7737582 https://news.ycombinator.com/item?id=7737582

sanxiyn 12y ago
Argh, this is annoying indeed. And yes, compiler is correct not to autovectorize in this case then.
- TheLoneWolfling 12y ago
  Why?
  - X-Istence 12y ago
    Different integer wrapping semantics I assume.
    - ygra 12y ago
      I wonder, though, because signed overflow is already undefined in C. The compiler could do anything there and call it correct.