From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-xd2b.google.com (mail-io1-xd2b.google.com [IPv6:2607:f8b0:4864:20::d2b]) by sourceware.org (Postfix) with ESMTPS id 7FB9B386100C for ; Tue, 3 Aug 2021 15:22:48 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 7FB9B386100C Received: by mail-io1-xd2b.google.com with SMTP id m13so24642997iol.7 for ; Tue, 03 Aug 2021 08:22:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=h9y3D7QwVyjFJDO9CLm9FwR5Z3XaXeZMI7IApV44euY=; b=ILitGu6JGgsk73Ysjw0lM6BFPiQOR4n0cgwxYiw1lzVrPwK9UgknOk2dnv6GymsJxe /lDZfStoeRYzyzpXPibq1Jxf1pX6ijhPQMsV9wZo9RW4YmnIFuxJkSNQ5v9Sb+t9Dm29 fSo2p+cqn9OP41gkyDNn8XksVhWKESiX7Ul/ONTEsF+XKy5maww4lE+LhEhvnW2nx5cI dw/41TVGjw+Sq7dOTmoc/Kq49elgroWLp0UTWxGKhBqKEaN3uzC/Fbn5BDw+3A66whLS 3NmR4s9p3fG65eVj9dsmwJAVIHE2FIXb4knj4GMeu8FkqP+jaV9g43NgmOucMlb0uP5V EYMg== X-Gm-Message-State: AOAM531WAnSvy84bSmS/D0LuidUVcM5vwpDIAxcr8O2qa4qsxxIOa7Id H+i73NCHQpdVShK4Oe2hMVoQyHK+04R20QerxgM= X-Google-Smtp-Source: ABdhPJxF8+ctPcu3BSDUaxaY0MxFAcULsLXgVitweKGK4XYGUw4WBP6rC88xpmiprgiTG1GJzkBxT/gzTGl9BWoEbmc= X-Received: by 2002:a02:2348:: with SMTP id u69mr8815603jau.141.1628004167817; Tue, 03 Aug 2021 08:22:47 -0700 (PDT) MIME-Version: 1.0 References: <9fd8bc30-f7d1-0171-4147-d570413f7a62@foss.st.com> <1d306b96-daa5-3a47-5e3e-d07ddd56dcf4@foss.st.com> In-Reply-To: From: Christophe Lyon Date: Tue, 3 Aug 2021 17:22:36 +0200 Message-ID: Subject: Re: [ARM] PR98435: Missed optimization in expanding vector constructor To: Prathamesh Kulkarni Cc: Kyrylo Tkachov , gcc Patches X-Spam-Status: No, score=-3.1 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, HTML_MESSAGE, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 03 Aug 2021 15:22:51 -0000 On Tue, Aug 3, 2021 at 12:57 PM Prathamesh Kulkarni < prathamesh.kulkarni@linaro.org> wrote: > On Tue, 3 Aug 2021 at 14:59, Christophe Lyon > 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 > wrote: > >> > > >> > > >> > > >> > > -----Original Message----- > >> > > From: Prathamesh Kulkarni > >> > > Sent: 06 July 2021 08:06 > >> > > To: Christophe LYON > >> > > Cc: Kyrylo Tkachov ; gcc Patches >> > > patches@gcc.gnu.org> > >> > > Subject: Re: [ARM] PR98435: Missed optimization in expanding vector > >> > > constructor > >> > > > >> > > On Thu, 1 Jul 2021 at 16:26, Prathamesh Kulkarni > >> > > wrote: > >> > > > > >> > > > On Wed, 30 Jun 2021 at 20:51, Christophe LYON > >> > > > wrote: > >> > > > > > >> > > > > > >> > > > > On 29/06/2021 12:46, Prathamesh Kulkarni wrote: > >> > > > > > On Mon, 28 Jun 2021 at 14:48, Christophe LYON > >> > > > > > wrote: > >> > > > > >> > >> > > > > >> On 28/06/2021 10:40, Kyrylo Tkachov via Gcc-patches wrote: > >> > > > > >>>> -----Original Message----- > >> > > > > >>>> From: Prathamesh Kulkarni > >> > > > > >>>> Sent: 28 June 2021 09:38 > >> > > > > >>>> To: Kyrylo Tkachov > >> > > > > >>>> Cc: Christophe Lyon ; gcc > Patches > >> > > >> > > > > >>>> patches@gcc.gnu.org> > >> > > > > >>>> Subject: Re: [ARM] PR98435: Missed optimization in > expanding > >> > > vector > >> > > > > >>>> constructor > >> > > > > >>>> > >> > > > > >>>> On Thu, 24 Jun 2021 at 22:01, Kyrylo Tkachov > >> > > > >> > > > > >>>> wrote: > >> > > > > >>>>> > >> > > > > >>>>>> -----Original Message----- > >> > > > > >>>>>> From: Prathamesh Kulkarni < > prathamesh.kulkarni@linaro.org> > >> > > > > >>>>>> Sent: 14 June 2021 09:02 > >> > > > > >>>>>> To: Christophe Lyon > >> > > > > >>>>>> Cc: gcc Patches ; Kyrylo > Tkachov > >> > > > > >>>>>> > >> > > > > >>>>>> Subject: Re: [ARM] PR98435: Missed optimization in > expanding > >> > > vector > >> > > > > >>>>>> constructor > >> > > > > >>>>>> > >> > > > > >>>>>> On Wed, 9 Jun 2021 at 15:58, Prathamesh Kulkarni > >> > > > > >>>>>> wrote: > >> > > > > >>>>>>> On Fri, 4 Jun 2021 at 13:15, Christophe Lyon > >> > > > > >>>> > >> > > > > >>>>>> wrote: > >> > > > > >>>>>>>> On Fri, 4 Jun 2021 at 09:27, Prathamesh Kulkarni via > Gcc- > >> > > patches > >> > > > > >>>>>>>> wrote: > >> > > > > >>>>>>>>> Hi, > >> > > > > >>>>>>>>> As mentioned in PR, for the following test-case: > >> > > > > >>>>>>>>> > >> > > > > >>>>>>>>> #include > >> > > > > >>>>>>>>> > >> > > > > >>>>>>>>> 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" > >> > > > > >>>>> - [(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 ? Because using mode > resulted > >> > > in lot > >> > > > > >>>> of build errors. > >> > > > > >>>> Also, I think the comparison should be inverted, ie, > GET_MODE_SIZE > >> > > > > >>>> (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__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__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)) > >> > > > 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? 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__ARITH > >> > > > > >>>>>>>> and possibly beware of issues with iwmmxt :-) > >> > > > > >>>>>>>> > >> > > > > >>>>>>>> Christophe > >> > > > > >>>>>>>> > >> > > > > >>>>>>>>> Thanks, > >> > > > > >>>>>>>>> Prathamesh >