On Sat, 29 Apr 2023 10:46:37 PDT (-0700), jeffreya...@gmail.com wrote:
On 4/29/23 11:28, Palmer Dabbelt wrote:
On Sat, 29 Apr 2023 10:21:53 PDT (-0700), gcc-patches@gcc.gnu.org wrote:
On Sat, Apr 29, 2023 at 8:06 AM Jeff Law via Gcc-patches <
gcc-patches@gcc.gnu.org> wrote:
On 4/28/23 20:55, Li, Pan2 wrote:
> Thanks Jeff for comments.
>
> It makes sense to me. For the EQ operator we should have CONSTM1.
That's not the way I interpret the RVV documentation. Of course it's
not terribly clear. I guess one could do some experiments with qemu
or try to dig into the sail code and figure out the intent from those.
QEMU specifically takes advantage of the behavior Andrew is pointing out
it the spec, and will soon do so more aggressively (assuming the patches
Daniel just sent out get merged).
Yea. And taking advantage of that behavior is definitely a performance
issue for QEMU. There's still work to do though. QEMU on vector code
is running crazy slow.
I guess we're kind of off the rails for a GCC patch, but that's
definately true. Across the board RVV is going to just need a lot of
work, it's very different than SVE or AVX.
Unfortunately QEMU performance isn't really a priority on our end, but
it's great to see folks digging into it.
