This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [PATCH, rs6000] Fix PR83789: __builtin_altivec_lvx fails for powerpc for altivec-4.c
On Wed, Mar 21, 2018 at 09:10:38PM -0500, Peter Bergner wrote:
> On 3/21/18 7:37 PM, Segher Boessenkool wrote:
> > On Wed, Mar 21, 2018 at 12:47:41PM -0500, Peter Bergner wrote:
> >> I'll note that GCC 7 does not need any of the changes to rs6000-p8swap.c,
> >> since that file doesn't exist and doesn't need to exist in GCC 7, so I've
> >> left those changes out.
> >
> > Did that same code live in rs6000.c in GCC 7, or is it new since
> > rs6000-p8swap.c was split off from there? And what about GCC 6?
>
> The trunk patch's changes to rs6000-p8swap.c were to rs6000_gen_lvx and
> rs6000_gen_stvx and those are new to GCC 8. They are used as part of
> Kelvin's optimization that changes the little endian unfriendly vsx
> loads and stores that require swaps, with the altivec lvx/stvx which
> do not need swaps. That optimization was new to GCC 8, so there was
> no need for the rs6000-p8swap.c changes.
Thanks for looking.
> If you're asking about whether we also need to backport to GCC 6, I
> believe Kaushik said in the bugzilla that he only encountered the
> ICE on GCC 7 and trunk, so I don't think we need a GCC 6 backport.
Uh yes, that is what I meant. Okay, since we have no way to check if
it fixes anything, let's not backport it to 6.
Segher