On Thu, Jun 24, 2021 at 6:29 PM Kyrylo Tkachov via Gcc-patches <
gcc-patches@gcc.gnu.org> wrote:
>
>
> > -----Original Message-----
> > From: Prathamesh Kulkarni <prathamesh.kulka...@linaro.org>
> > Sent: 24 June 2021 12:11
> > To: gcc Patches <gcc-patches@gcc.gnu.org>; Kyrylo Tkachov
> > <kyrylo.tkac...@arm.com>
> > Subject: [ARM] PR66791: Replace builtins for vdup_n and vmov_n intrinsics
> >
> > Hi,
> > This patch replaces builtins for vdup_n and vmov_n.
> > The patch results in regression for pr51534.c.
> > Consider following function:
> >
> > uint8x8_t f1 (uint8x8_t a) {
> > return vcgt_u8(a, vdup_n_u8(0));
> > }
> >
> > code-gen before patch:
> > f1:
> > vmov.i32 d16, #0 @ v8qi
> > vcgt.u8 d0, d0, d16
> > bx lr
> >
> > code-gen after patch:
> > f1:
> > vceq.i8 d0, d0, #0
> > vmvn d0, d0
> > bx lr
> >
> > I am not sure which one is better tho ?
>
>
Hi Prathamesh,
This patch introduces a regression on non-hardfp configs (eg
arm-linux-gnueabi or arm-eabi):
FAIL: gcc:gcc.target/arm/arm.exp=gcc.target/arm/pr51534.c
scan-assembler-times vmov.i32[ \t]+[dD][0-9]+, #0xffffffff 3
FAIL: gcc:gcc.target/arm/arm.exp=gcc.target/arm/pr51534.c
scan-assembler-times vmov.i32[ \t]+[qQ][0-9]+, #4294967295 3
Can you fix this?
Thanks
Christophe
> I think they're equivalent in practice, in any case the patch itself is
> good (move away from RTL builtins).
> Ok.
> Thanks,
> Kyrill
>
> >
> > Also, this patch regressed bf16_dup.c on arm-linux-gnueabi,
> > which is due to a missed opt in lowering. I had filed it as
> > PR98435, and posted a fix for it here:
> > https://gcc.gnu.org/pipermail/gcc-patches/2021-June/572648.html
> >
> > Thanks,
> > Prathamesh
>
