https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88398
ktkachov at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2018-12-07
CC| |ktkachov at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #6 from ktkachov at gcc dot gnu.org ---
(In reply to Richard Biener from comment #5)
> Well, the main issue is that the loop has two exits which is something the
> vectorizer doesn't support (with a hard check). Jakub explains why that is
> so.
>
> You could change the loop to sth like
>
> unsigned char *p = cur + pos;
> int len = 0;
> int diff_pos = __INT_MAX__;
> while (++len != max)
> if (p[len] != cur[len])
> diff_pos = len < diff_pos ? len : diff_pos;
> return cur[diff_pos];
>
> which then runs into a limitation recently reported (two dependent
> reductions not recognized).
Could GCC generate this version and select it at runtime if max is sufficiently
large?
