> -----Original Message-----
> From: Prathamesh Kulkarni <prathamesh.kulka...@linaro.org>
> Sent: 24 August 2021 09:01
> To: Christophe Lyon <christophe.lyon....@gmail.com>
> Cc: Kyrylo Tkachov <kyrylo.tkac...@arm.com>; gcc Patches <gcc-
> patc...@gcc.gnu.org>
> Subject: Re: [ARM] PR66791: Replace builtins for vdup_n and vmov_n
> intrinsics
>
> On Tue, 17 Aug 2021 at 11:55, Prathamesh Kulkarni
> <prathamesh.kulka...@linaro.org> wrote:
> >
> > On Thu, 12 Aug 2021 at 19:04, Christophe Lyon
> > <christophe.lyon....@gmail.com> wrote:
> > >
> > >
> > >
> > > On Thu, Aug 12, 2021 at 1:54 PM Prathamesh Kulkarni
> <prathamesh.kulka...@linaro.org> wrote:
> > >>
> > >> On Wed, 11 Aug 2021 at 22:23, Christophe Lyon
> > >> <christophe.lyon....@gmail.com> wrote:
> > >> >
> > >> >
> > >> >
> > >> > On Thu, Jun 24, 2021 at 6:29 PM Kyrylo Tkachov via Gcc-patches <gcc-
> patc...@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?
> > >> The issue is, for following test:
> > >>
> > >> #include <arm_neon.h>
> > >>
> > >> uint8x8_t f1 (uint8x8_t a) {
> > >> return vcge_u8(a, vdup_n_u8(0));
> > >> }
> > >>
> > >> armhf code-gen:
> > >> f1:
> > >> vmov.i32 d0, #0xffffffff @ v8qi
> > >> bx lr
> > >>
> > >> arm softfp code-gen:
> > >> f1:
> > >> mov r0, #-1
> > >> mov r1, #-1
> > >> bx lr
> > >>
> > >> The code-gen for both is same upto split2 pass:
> > >>
> > >> (insn 10 6 11 2 (set (reg/i:V8QI 16 s0)
> > >> (const_vector:V8QI [
> > >> (const_int -1 [0xffffffffffffffff]) repeated x8
> > >> ])) "foo.c":5:1 1052 {*neon_movv8qi}
> > >> (expr_list:REG_EQUAL (const_vector:V8QI [
> > >> (const_int -1 [0xffffffffffffffff]) repeated x8
> > >> ])
> > >> (nil)))
> > >> (insn 11 10 13 2 (use (reg/i:V8QI 16 s0)) "foo.c":5:1 -1
> > >> (nil))
> > >>
> > >> and for softfp target, split2 pass splits the assignment to r0 and r1:
> > >>
> > >> (insn 15 6 16 2 (set (reg:SI 0 r0)
> > >> (const_int -1 [0xffffffffffffffff])) "foo.c":5:1 740
> {*thumb2_movsi_vfp}
> > >> (nil))
> > >> (insn 16 15 11 2 (set (reg:SI 1 r1 [+4 ])
> > >> (const_int -1 [0xffffffffffffffff])) "foo.c":5:1 740
> {*thumb2_movsi_vfp}
> > >> (nil))
> > >> (insn 11 16 13 2 (use (reg/i:V8QI 0 r0)) "foo.c":5:1 -1
> > >> (nil))
> > >>
> > >> I suppose we could use a dg-scan for r[0-9]+, #-1 for softfp targets ?
> > >>
> > > Yes, probably, or try with check-function-bodies.
> > Hi,
> > Sorry for the late response. Does the attached patch look OK ?
> ping https://gcc.gnu.org/pipermail/gcc-patches/2021-August/577532.html
Ok.
Thanks,
Kyrill
>
> Thanks,
> Prathamesh
> >
> > Thanks,
> > Prathamesh
> > >
> > > Christophe
> > >
> > >> Thanks,
> > >> Prathamesh
> > >> >
> > >> > 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
