On Wed, Jan 9, 2019 at 9:50 AM Andrew Haley <a...@redhat.com> wrote: > > On 1/9/19 9:45 AM, Kyrill Tkachov wrote: > > Hi Kay, > > > > On 09/01/19 08:29, Kay F. Jahnke wrote: > >> Hi there! > >> > >> I am developing software which tries to deliberately exploit the > >> compiler's autovectorization facilities by feeding data in > >> autovectorization-friendly loops. I'm currently using both g++ and > >> clang++ to see how well this approach works. Using simple arithmetic, I > >> often get good results. To widen the scope of my work, I was looking for > >> documentation on which constructs would be recognized by the > >> autovectorization stage, and found > >> > >> https://www.gnu.org/software/gcc/projects/tree-ssa/vectorization.html > >> > > > > Yeah, that page hasn't been updated in ages AFAIK. > > > >> By the looks of it, this document has not seen any changes for several > >> years. Has development on the autovectorization stage stopped, or is > >> there simply no documentation? > >> > > > > There's plenty of work being done on auto-vectorisation in GCC. > > Auto-vectorisation is a performance optimisation and as such is not really > > a user-visible feature that absolutely requires user documentation. > > I don't agree. Sometimes vectorization is critical. It would be nice > to have a warning which would fire if vectorization failed. That would > surely help the OP.
That would help certainly : the user could get some information out today with the debug dumps - however they are designed more for the compiler writers rather than users. regards Ramana
