PING^3 [PATCH] x86: Update memcpy/memset inline strategies for -mtune=generic

["H.J. Lu" <hjl.tools@gmail.com>]

On Mon, Sep 13, 2021 at 6:38 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Tue, Sep 7, 2021 at 8:01 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > On Sun, Aug 22, 2021 at 8:28 AM H.J. Lu <hjl.tools@gmail.com> wrote:
> > >
> > > On Tue, Mar 23, 2021 at 09:19:38AM +0100, Richard Biener wrote:
> > > > On Tue, Mar 23, 2021 at 3:41 AM Hongyu Wang <wwwhhhyyy333@gmail.com> wrote:
> > > > >
> > > > > > Hongyue, please collect code size differences on SPEC CPU 2017 and
> > > > > > eembc.
> > > > >
> > > > > Here is code size difference for this patch
> > > >
> > > > Thanks, nothing too bad although slightly larger impacts than envisioned.
> > > >
> > >
> > > PING.
> > >
> > > OK for master branch?
> > >
> > > Thanks.
> > >
> > > H.J.
> > >  ---
> > > Simplify memcpy and memset inline strategies to avoid branches for
> > > -mtune=generic:
> > >
> > > 1. With MOVE_RATIO and CLEAR_RATIO == 17, GCC will use integer/vector
> > >    load and store for up to 16 * 16 (256) bytes when the data size is
> > >    fixed and known.
> > > 2. Inline only if data size is known to be <= 256.
> > >    a. Use "rep movsb/stosb" with simple code sequence if the data size
> > >       is a constant.
> > >    b. Use loop if data size is not a constant.
> > > 3. Use memcpy/memset libray function if data size is unknown or > 256.
> > >
> >
> > PING:
> >
> > https://gcc.gnu.org/pipermail/gcc-patches/2021-August/577889.html
> >
>
> PING.  This should fix:
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102294
>

PING.

-- 
H.J.