On Thu, Aug 5, 2021 at 2:28 PM Prathamesh Kulkarni < prathamesh.kulka...@linaro.org> wrote:
> On Tue, 3 Aug 2021 at 20:52, Christophe Lyon > <christophe.lyon....@gmail.com> wrote: > > > > > > > > On Tue, Aug 3, 2021 at 12:57 PM Prathamesh Kulkarni < > prathamesh.kulka...@linaro.org> wrote: > >> > >> On Tue, 3 Aug 2021 at 14:59, Christophe Lyon > >> <christophe.lyon....@gmail.com> wrote: > >> > > >> > > >> > > >> > On Tue, Jul 6, 2021 at 11:26 AM Prathamesh Kulkarni via Gcc-patches < > gcc-patches@gcc.gnu.org> wrote: > >> >> > >> >> On Tue, 6 Jul 2021 at 13:33, Kyrylo Tkachov <kyrylo.tkac...@arm.com> > wrote: > >> >> > > >> >> > > >> >> > > >> >> > > -----Original Message----- > >> >> > > From: Prathamesh Kulkarni <prathamesh.kulka...@linaro.org> > >> >> > > Sent: 06 July 2021 08:06 > >> >> > > To: Christophe LYON <christophe.l...@foss.st.com> > >> >> > > Cc: Kyrylo Tkachov <kyrylo.tkac...@arm.com>; gcc Patches <gcc- > >> >> > > patc...@gcc.gnu.org> > >> >> > > Subject: Re: [ARM] PR98435: Missed optimization in expanding > vector > >> >> > > constructor > >> >> > > > >> >> > > On Thu, 1 Jul 2021 at 16:26, Prathamesh Kulkarni > >> >> > > <prathamesh.kulka...@linaro.org> wrote: > >> >> > > > > >> >> > > > On Wed, 30 Jun 2021 at 20:51, Christophe LYON > >> >> > > > <christophe.l...@foss.st.com> wrote: > >> >> > > > > > >> >> > > > > > >> >> > > > > On 29/06/2021 12:46, Prathamesh Kulkarni wrote: > >> >> > > > > > On Mon, 28 Jun 2021 at 14:48, Christophe LYON > >> >> > > > > > <christophe.l...@foss.st.com> wrote: > >> >> > > > > >> > >> >> > > > > >> On 28/06/2021 10:40, Kyrylo Tkachov via Gcc-patches wrote: > >> >> > > > > >>>> -----Original Message----- > >> >> > > > > >>>> From: Prathamesh Kulkarni < > prathamesh.kulka...@linaro.org> > >> >> > > > > >>>> Sent: 28 June 2021 09:38 > >> >> > > > > >>>> To: Kyrylo Tkachov <kyrylo.tkac...@arm.com> > >> >> > > > > >>>> Cc: Christophe Lyon <christophe.l...@linaro.org>; gcc > Patches > >> >> > > <gcc- > >> >> > > > > >>>> patc...@gcc.gnu.org> > >> >> > > > > >>>> Subject: Re: [ARM] PR98435: Missed optimization in > expanding > >> >> > > vector > >> >> > > > > >>>> constructor > >> >> > > > > >>>> > >> >> > > > > >>>> On Thu, 24 Jun 2021 at 22:01, Kyrylo Tkachov > >> >> > > <kyrylo.tkac...@arm.com> > >> >> > > > > >>>> wrote: > >> >> > > > > >>>>> > >> >> > > > > >>>>>> -----Original Message----- > >> >> > > > > >>>>>> From: Prathamesh Kulkarni < > prathamesh.kulka...@linaro.org> > >> >> > > > > >>>>>> Sent: 14 June 2021 09:02 > >> >> > > > > >>>>>> To: Christophe Lyon <christophe.l...@linaro.org> > >> >> > > > > >>>>>> Cc: gcc Patches <gcc-patches@gcc.gnu.org>; Kyrylo > Tkachov > >> >> > > > > >>>>>> <kyrylo.tkac...@arm.com> > >> >> > > > > >>>>>> Subject: Re: [ARM] PR98435: Missed optimization in > expanding > >> >> > > vector > >> >> > > > > >>>>>> constructor > >> >> > > > > >>>>>> > >> >> > > > > >>>>>> On Wed, 9 Jun 2021 at 15:58, Prathamesh Kulkarni > >> >> > > > > >>>>>> <prathamesh.kulka...@linaro.org> wrote: > >> >> > > > > >>>>>>> On Fri, 4 Jun 2021 at 13:15, Christophe Lyon > >> >> > > > > >>>> <christophe.l...@linaro.org> > >> >> > > > > >>>>>> wrote: > >> >> > > > > >>>>>>>> On Fri, 4 Jun 2021 at 09:27, Prathamesh Kulkarni > via Gcc- > >> >> > > patches > >> >> > > > > >>>>>>>> <gcc-patches@gcc.gnu.org> wrote: > >> >> > > > > >>>>>>>>> Hi, > >> >> > > > > >>>>>>>>> As mentioned in PR, for the following test-case: > >> >> > > > > >>>>>>>>> > >> >> > > > > >>>>>>>>> #include <arm_neon.h> > >> >> > > > > >>>>>>>>> > >> >> > > > > >>>>>>>>> bfloat16x4_t f1 (bfloat16_t a) > >> >> > > > > >>>>>>>>> { > >> >> > > > > >>>>>>>>> return vdup_n_bf16 (a); > >> >> > > > > >>>>>>>>> } > >> >> > > > > >>>>>>>>> > >> >> > > > > >>>>>>>>> bfloat16x4_t f2 (bfloat16_t a) > >> >> > > > > >>>>>>>>> { > >> >> > > > > >>>>>>>>> return (bfloat16x4_t) {a, a, a, a}; > >> >> > > > > >>>>>>>>> } > >> >> > > > > >>>>>>>>> > >> >> > > > > >>>>>>>>> Compiling with arm-linux-gnueabi -O3 -mfpu=neon > -mfloat- > >> >> > > > > >>>> abi=softfp > >> >> > > > > >>>>>>>>> -march=armv8.2-a+bf16+fp16 results in f2 not being > >> >> > > vectorized: > >> >> > > > > >>>>>>>>> > >> >> > > > > >>>>>>>>> f1: > >> >> > > > > >>>>>>>>> vdup.16 d16, r0 > >> >> > > > > >>>>>>>>> vmov r0, r1, d16 @ v4bf > >> >> > > > > >>>>>>>>> bx lr > >> >> > > > > >>>>>>>>> > >> >> > > > > >>>>>>>>> f2: > >> >> > > > > >>>>>>>>> mov r3, r0 @ __bf16 > >> >> > > > > >>>>>>>>> adr r1, .L4 > >> >> > > > > >>>>>>>>> ldrd r0, [r1] > >> >> > > > > >>>>>>>>> mov r2, r3 @ __bf16 > >> >> > > > > >>>>>>>>> mov ip, r3 @ __bf16 > >> >> > > > > >>>>>>>>> bfi r1, r2, #0, #16 > >> >> > > > > >>>>>>>>> bfi r0, ip, #0, #16 > >> >> > > > > >>>>>>>>> bfi r1, r3, #16, #16 > >> >> > > > > >>>>>>>>> bfi r0, r2, #16, #16 > >> >> > > > > >>>>>>>>> bx lr > >> >> > > > > >>>>>>>>> > >> >> > > > > >>>>>>>>> This seems to happen because vec_init pattern in > neon.md > >> >> > > has VDQ > >> >> > > > > >>>>>> mode > >> >> > > > > >>>>>>>>> iterator, which doesn't include V4BF. In attached > patch, I > >> >> > > changed > >> >> > > > > >>>>>>>>> mode > >> >> > > > > >>>>>>>>> to VDQX which seems to work for the test-case, and > the > >> >> > > compiler > >> >> > > > > >>>> now > >> >> > > > > >>>>>> generates: > >> >> > > > > >>>>>>>>> f2: > >> >> > > > > >>>>>>>>> vdup.16 d16, r0 > >> >> > > > > >>>>>>>>> vmov r0, r1, d16 @ v4bf > >> >> > > > > >>>>>>>>> bx lr > >> >> > > > > >>>>>>>>> > >> >> > > > > >>>>>>>>> However, the pattern is also gated on > TARGET_HAVE_MVE > >> >> > > and I am > >> >> > > > > >>>>>> not > >> >> > > > > >>>>>>>>> sure if either VDQ or VDQX are correct modes for > MVE since > >> >> > > MVE > >> >> > > > > >>>> has > >> >> > > > > >>>>>>>>> only 128-bit vectors ? > >> >> > > > > >>>>>>>>> > >> >> > > > > >>>>>>>> I think patterns common to both Neon and MVE should > be > >> >> > > moved to > >> >> > > > > >>>>>>>> vec-common.md, I don't know why such patterns were > left in > >> >> > > > > >>>> neon.md. > >> >> > > > > >>>>>>> Since we end up calling neon_expand_vector_init for > both > >> >> > > NEON and > >> >> > > > > >>>> MVE, > >> >> > > > > >>>>>>> I am not sure if we should separate the pattern ? > >> >> > > > > >>>>>>> Would it make sense to FAIL if the mode size isn't > 16 bytes for > >> >> > > MVE as > >> >> > > > > >>>>>>> in attached patch so > >> >> > > > > >>>>>>> it will call neon_expand_vector_init only for > 128-bit vectors ? > >> >> > > > > >>>>>>> Altho hard-coding 16 in the pattern doesn't seem a > good idea to > >> >> > > me > >> >> > > > > >>>> either. > >> >> > > > > >>>>>> ping https://gcc.gnu.org/pipermail/gcc-patches/2021- > >> >> > > June/572342.html > >> >> > > > > >>>>>> (attaching patch as text). > >> >> > > > > >>>>>> > >> >> > > > > >>>>> --- a/gcc/config/arm/neon.md > >> >> > > > > >>>>> +++ b/gcc/config/arm/neon.md > >> >> > > > > >>>>> @@ -459,10 +459,12 @@ > >> >> > > > > >>>>> ) > >> >> > > > > >>>>> > >> >> > > > > >>>>> (define_expand "vec_init<mode><V_elem_l>" > >> >> > > > > >>>>> - [(match_operand:VDQ 0 "s_register_operand") > >> >> > > > > >>>>> + [(match_operand:VDQX 0 "s_register_operand") > >> >> > > > > >>>>> (match_operand 1 "" "")] > >> >> > > > > >>>>> "TARGET_NEON || TARGET_HAVE_MVE" > >> >> > > > > >>>>> { > >> >> > > > > >>>>> + if (TARGET_HAVE_MVE && GET_MODE_SIZE (GET_MODE > >> >> > > > > >>>> (operands[0])) != 16) > >> >> > > > > >>>>> + FAIL; > >> >> > > > > >>>>> neon_expand_vector_init (operands[0], > operands[1]); > >> >> > > > > >>>>> DONE; > >> >> > > > > >>>>> }) > >> >> > > > > >>>>> > >> >> > > > > >>>>> I think we should move this to vec-common.md like > Christophe > >> >> > > said. > >> >> > > > > >>>>> Perhaps rather than making it FAIL for non-16 MVE > sizes we just > >> >> > > disable it in > >> >> > > > > >>>> the expander condition? > >> >> > > > > >>>>> "TARGET_NEON || (TARGET_HAVE_MVE && GET_MODE_SIZE (< > >> >> > > > > >>>> VDQ>mode) != 16)" > >> >> > > > > >>>> Is it OK to use <MODE>mode ? Because using <VDQ>mode > resulted > >> >> > > in lot > >> >> > > > > >>>> of build errors. > >> >> > > > > >>>> Also, I think the comparison should be inverted, ie, > GET_MODE_SIZE > >> >> > > > > >>>> (<MODE>mode) == 16 since > >> >> > > > > >>>> we want to make the pattern pass if target is MVE and > vector size is > >> >> > > 16 bytes ? > >> >> > > > > >>>> Do these changes in attached patch look OK ? > >> >> > > > > >>> Yes, you're right. > >> >> > > > > >> > >> >> > > > > >> Can't this be ARM_HAVE_<MODE>_ARITH like in most > expanders in > >> >> > > vec-common.md? > >> >> > > > > >> > >> >> > > > > >> (maybe with a && !TARGET_REALLY_IWMMXT if needed) > >> >> > > > > > I wonder if this should be ARM_HAVE_<MODE>_LDST instead > since > >> >> > > we're > >> >> > > > > > initializing the vector ? > >> >> > > > > > >> >> > > > > > >> >> > > > > Well, it really depends on which modes you want to enable. > >> >> > > > > > >> >> > > > > > >> >> > > > > Looks like your move VDQ -> VDQ adds V4BF, V8BF and DI. > >> >> > > > > > >> >> > > > > Are they all OK for Neon? > >> >> > > > > > >> >> > > > > They are not OK for MVE. > >> >> > > > > > >> >> > > > > Ideally you could add testcases to cover to the supported and > >> >> > > > > unsupported modes for both Neon and MVE.\ > >> >> > > > > > >> >> > > > > Before your patch, the expander is enabled for MVE for 64 > bit modes > >> >> > > > > (V8QI, V4HI, V2SI): what happens in this case? Does the > compiler crash > >> >> > > > > or is there something else preventing the match? > >> >> > > > Hi, > >> >> > > > Apparently there is VALID_MVE_MODE macro, so is it better to > use: > >> >> > > > TARGET_NEON || (TARGET_HAVE_MVE && > >> >> > > VALID_MVE_MODE(<MODE>mode)) > >> >> > > > as in the attached patch ? > >> >> > > >> >> > The change is ok. I would like to see some testcases like > Christophe suggested, but this patch just moves the expander around rather > than introducing new functionality. > >> >> Hi Kyrill, > >> >> As mentioned in the first email, the patch improves code-gen for > >> >> following test-case: > >> >> > >> >> bfloat16x4_t f (bfloat16_t a) > >> >> { > >> >> return (bfloat16x4_t) {a, a, a, a}; > >> >> } > >> >> > >> >> Before patch: > >> >> f: > >> >> mov r3, r0 @ __bf16 > >> >> adr r1, .L4 > >> >> ldrd r0, [r1] > >> >> mov r2, r3 @ __bf16 > >> >> mov ip, r3 @ __bf16 > >> >> bfi r1, r2, #0, #16 > >> >> bfi r0, ip, #0, #16 > >> >> bfi r1, r3, #16, #16 > >> >> bfi r0, r2, #16, #16 > >> >> bx lr > >> >> > >> >> After patch: > >> >> f: > >> >> vdup.16 d16, r0 > >> >> vmov r0, r1, d16 @ v4bf > >> >> bx lr > >> >> > >> >> because the patch changes mode from VDQ to VDQX to accommodate bf > modes. > >> >> I have included the test in the attached patch. > >> >> I think Christophe's concerns were mainly about the right modes > >> >> getting enabled for MVE. > >> >> Unfortunately, I am not sure how to test for that because the FE > >> >> catches invalid modes, and we don't > >> >> end up hitting the pattern. > >> >> > >> > > >> > Hi Prathamesh, > >> > > >> > The new testcase fails on arm-linux-gnueabihf: > >> > FAIL: gcc.target/arm/simd/pr98435.c (test for excess errors) > >> > Excess errors: > >> > > /aci-gcc-fsf/builds/gcc-fsf-gccsrc/sysroot-arm-none-linux-gnueabihf/usr/include/gnu/stubs.h:7:11: > fatal error: gnu/stubs-soft.h: No such file or directory > >> > compilation terminated. > >> > > >> > Because you don't check whether -mfloat-abi=softfp is actually > supported. > >> > > >> > Can you fix that? > >> Oops, sorry about that. > >> The attached patch fixes the test by requiring arm_softfloat and makes > >> it UNSUPPORTED on arm-linux-gnueabihf. > >> Does it look OK ? > >> > > > > I don't think that's right: it would make the test unsupported if softfp > is not the default even if the toolchain has the needed multilibs. > > Did you check eg. with arm-eabi and multilibs enabled? > Ah OK, thanks for pointing it out! > Does the attached patch look correct ? > > I don't think: this would skip the test even if the toolchain has multilibs enabled. Did you check eg. with arm-eabi and multilibs enabled and the usual option overrides? Christophe Thanks, > Prathamesh > > > > Christophe > > > >> > >> Thanks, > >> Prathamesh > >> > > >> > Thanks > >> > > >> > Christophe > >> > > >> > > >> >> > >> >> Thanks, > >> >> Prathamesh > >> >> > Thanks, > >> >> > Kyrill > >> >> > > >> >> > > ping > https://gcc.gnu.org/pipermail/gcc-patches/2021-July/574206.html > >> >> > > > >> >> > > Thanks, > >> >> > > Prathamesh > >> >> > > > > >> >> > > > Thanks, > >> >> > > > Prathamesh > >> >> > > > > > >> >> > > > > > >> >> > > > > Thanks, > >> >> > > > > > >> >> > > > > > >> >> > > > > Christophe > >> >> > > > > > >> >> > > > > > >> >> > > > > > Thanks, > >> >> > > > > > Prathamesh > >> >> > > > > >> > >> >> > > > > >> Christophe > >> >> > > > > >> > >> >> > > > > >> > >> >> > > > > >>> Ok. > >> >> > > > > >>> Thanks, > >> >> > > > > >>> Kyrill > >> >> > > > > >>> > >> >> > > > > >>> > >> >> > > > > >>>> Thanks, > >> >> > > > > >>>> Prathamesh > >> >> > > > > >>>>> Thanks, > >> >> > > > > >>>>> Kyrill > >> >> > > > > >>>>> > >> >> > > > > >>>>>> Thanks, > >> >> > > > > >>>>>> Prathamesh > >> >> > > > > >>>>>>> Thanks, > >> >> > > > > >>>>>>> Prathamesh > >> >> > > > > >>>>>>>> That being said, I suggest you look at other > similar patterns in > >> >> > > > > >>>>>>>> vec-common.md, most of which are gated on > >> >> > > > > >>>>>>>> ARM_HAVE_<MODE>_ARITH > >> >> > > > > >>>>>>>> and possibly beware of issues with iwmmxt :-) > >> >> > > > > >>>>>>>> > >> >> > > > > >>>>>>>> Christophe > >> >> > > > > >>>>>>>> > >> >> > > > > >>>>>>>>> Thanks, > >> >> > > > > >>>>>>>>> Prathamesh >