From: Ramana Radhakrishnan <ramana.gcc@googlemail.com>
To: Andrew Haley <aph@redhat.com>
Cc: Kyrill Tkachov <kyrylo.tkachov@foss.arm.com>,
"Kay F. Jahnke" <kfjahnke@gmail.com>,
"gcc@gcc.gnu.org" <gcc@gcc.gnu.org>
Subject: Re: autovectorization in gcc
Date: Wed, 09 Jan 2019 10:47:00 -0000 [thread overview]
Message-ID: <CAJA7tRbWAQfSum7BnLNrCmJXMnTWo7pc-3j2KiCCgzobMk1t=w@mail.gmail.com> (raw)
In-Reply-To: <2721bb39-ee4b-0202-d81d-e0b36d2059fa@redhat.com>
On Wed, Jan 9, 2019 at 9:50 AM Andrew Haley <aph@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
next prev parent reply other threads:[~2019-01-09 10:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-09 8:29 Kay F. Jahnke
2019-01-09 9:46 ` Kyrill Tkachov
2019-01-09 9:50 ` Andrew Haley
2019-01-09 9:56 ` Jonathan Wakely
2019-01-09 16:10 ` David Malcolm
2019-01-09 16:25 ` Jakub Jelinek
2019-01-10 8:19 ` Richard Biener
2019-01-10 11:11 ` Szabolcs Nagy
2019-01-09 16:26 ` David Malcolm
2019-01-09 10:47 ` Ramana Radhakrishnan [this message]
2019-01-10 9:24 ` Kay F. Jahnke
2019-01-10 11:18 ` Jonathan Wakely
2019-08-18 10:59 ` [wwwdocs PATCH] for " Gerald Pfeifer
2019-01-09 10:56 ` Kay F. Jahnke
2019-01-09 11:03 ` Jakub Jelinek
2019-01-09 11:21 ` Jakub Jelinek
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