From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qv1-xf2a.google.com (mail-qv1-xf2a.google.com [IPv6:2607:f8b0:4864:20::f2a]) by sourceware.org (Postfix) with ESMTPS id 524283955614 for ; Thu, 2 Jun 2022 09:11:21 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 524283955614 Received: by mail-qv1-xf2a.google.com with SMTP id l1so3185592qvh.1 for ; Thu, 02 Jun 2022 02:11:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=N+nxvpAbmxMO3gxqn+1rL/B+7a2xmdb3AMZMXQtDihw=; b=S7o8jGigDeW/ZHsAILHal0Vl4nz/elYkuN2KGDueiojtjbG3bGvpSGURfi5cAybsRR wo/fgtWXsqzmC3uoI8erMlZ6OvpNg1lBTOI78bUtIgVkbz3zaYkq9zE2knRkVG7iDpa0 VaHFmORra5AoDT0kWwVMwZalDYJUcZeNu9HBV7kiVoheHdksoRVWrt9y8iw6HObj8Feg yTwtRLc06bUvPOMY2NuvzfhU47sYwd2jbvcSb41C3UMZbQD2DPDXRcc37Ov+VUellrry AxdD6V4Ina5Caqt1t7BEAuEO03/KPzHcfASPdIBGk9dJrYTw35CZfort3idh4w39EVgD N5EQ== X-Gm-Message-State: AOAM533t0BqNKsy1ESSunlmZangOcRIWkdsSAypL+ws5Q8X+JVz8k8F1 pS9ri/3tX7K0sAl76197+Hpv5OG3ITYYZ8ElheKuY4sToSQ= X-Google-Smtp-Source: ABdhPJweC3TDzvUFaVyyEv0D1k7ISixZg2AZzYkw2F/s0zSLi8EnxSOJX3fTQlEbgk98x640HeY/AsHXkkVGxsQTvr4= X-Received: by 2002:a05:6214:2307:b0:432:e753:e0c4 with SMTP id gc7-20020a056214230700b00432e753e0c4mr56877409qvb.55.1654161080582; Thu, 02 Jun 2022 02:11:20 -0700 (PDT) MIME-Version: 1.0 References: <20220602010910.20587-1-hongtao.liu@intel.com> In-Reply-To: <20220602010910.20587-1-hongtao.liu@intel.com> From: Richard Biener Date: Thu, 2 Jun 2022 11:11:09 +0200 Message-ID: Subject: Re: [PATCH] Simplify (B * v + C) * D -> BD* v + CD when B, C, D are all INTEGER_CST. To: liuhongt Cc: GCC Patches Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-8.0 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org 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: Thu, 02 Jun 2022 09:11:24 -0000 On Thu, Jun 2, 2022 at 3:10 AM liuhongt via Gcc-patches wrote: > > Similar for (v + B) * C + D -> C * v + BCD. > Don't simplify it when there's overflow and overflow is UB for type v. > > There's new failure > > gcc.dg/vect/slp-11a.c scan-tree-dump-times vect "vectorizing stmts using SLP" 0 > > It's because the patch simplify different operations to mult + add and enables > SLP. So I adjust the testcase to prevent simplication by making the > multiplication result overflow. > > Also with -fwrapv, benchmark in the PR now 100% faster than > origin(scalar version). > > Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,} > Ok for trunk? > > gcc/ChangeLog: > > PR tree-optimization/53533 > * match.pd: Simplify (B * v + C) * D -> BD * v + CD and > (v + B) * C + D -> C * v + BCD when B,C,D are all INTEGER_CST, > and there's no overflow or TYPE_OVERFLOW_WRAP. > > gcc/testsuite/ChangeLog: > > * gcc.target/i386/pr53533-1.c: New test. > * gcc.target/i386/pr53533-2.c: New test. > * gcc.target/i386/pr53533-3.c: New test. > * gcc.target/i386/pr53533-4.c: New test. > * gcc.dg/vect/slp-11a.c: Adjust testcase. > --- > gcc/match.pd | 36 ++++++++++++++++++ > gcc/testsuite/gcc.dg/vect/slp-11a.c | 10 ++--- > gcc/testsuite/gcc.target/i386/pr53533-1.c | 23 ++++++++++++ > gcc/testsuite/gcc.target/i386/pr53533-2.c | 46 +++++++++++++++++++++++ > gcc/testsuite/gcc.target/i386/pr53533-3.c | 24 ++++++++++++ > gcc/testsuite/gcc.target/i386/pr53533-4.c | 46 +++++++++++++++++++++++ > 6 files changed, 180 insertions(+), 5 deletions(-) > create mode 100644 gcc/testsuite/gcc.target/i386/pr53533-1.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr53533-2.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr53533-3.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr53533-4.c > > diff --git a/gcc/match.pd b/gcc/match.pd > index 88c6c414881..b753f7bda3c 100644 > --- a/gcc/match.pd > +++ b/gcc/match.pd > @@ -489,6 +489,42 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) > (if (!overflow || TYPE_OVERFLOW_WRAPS (type)) > (mult @0 { wide_int_to_tree (type, mul); })))) > > +/* Similar to above, but there could be an extra add/sub between > + successive multuiplications. */ > +(simplify > + (mult:c (plus:c@4 (mult:c@5 @0 INTEGER_CST@1) INTEGER_CST@2) INTEGER_CST@3) since canonicalization puts INTEGER_CSTs last the :c should not be necessary. > + (if (single_use (@4) > + && single_use (@5)) since the resulting expression is not simple using :s instead of single_use (..) should work as well. > + (with { > + wi::overflow_type overflow; > + wi::overflow_type overflow2; > + wide_int mul = wi::mul (wi::to_wide (@1), wi::to_wide (@3), > + TYPE_SIGN (type), &overflow); > + wide_int add = wi::mul (wi::to_wide (@2), wi::to_wide (@3), > + TYPE_SIGN (type), &overflow2); > + } > + /* Skip folding on overflow. */ > + (if (!(overflow || overflow2) || TYPE_OVERFLOW_WRAPS (type)) > + (plus (mult @0 { wide_int_to_tree (type, mul); }) > + { wide_int_to_tree (type, add); }))))) > + > +/* Similar to above, but a multiplication between successive additions. */ > +(simplify > + (plus:c (mult:c@4 (plus:c@5 @0 INTEGER_CST@1) INTEGER_CST@2) INTEGER_CST@3) Likewise for :c and :s > + (if (single_use (@4) > + && single_use (@5)) > + (with { > + wi::overflow_type overflow; > + wi::overflow_type overflow2; > + wide_int mul = wi::mul (wi::to_wide (@1), wi::to_wide (@2), > + TYPE_SIGN (type), &overflow); > + wide_int add = wi::add (mul, wi::to_wide (@3), > + TYPE_SIGN (type), &overflow2); > + } > + /* Skip folding on overflow. */ > + (if (!(overflow || overflow2) || TYPE_OVERFLOW_WRAPS (type)) > + (plus (mult @0 @2) { wide_int_to_tree (type, add); }))))) when we go from (a + CST1) * CST2 to a * CST2 + CST1*CST2 we have to worry about CST1 == -a which would make (a+CST1) * INT_MAX not overflow but a * INT_MAX + CST1 * INT_MAX might. Is the overflow check for CST1 * INT_MAX sufficient to rule out that a * CST2 does not overflow when (a + CST1) * CST2 does not overflow? Consider a == 2, CST1 == -1, CST2 == INT_MAX, here 1 * INT_MAX does not overflow, nor does -1 * INT_MAX, but 2 * INT_MAX overflows and thus the resulting expression invokes undefined behavior. The same issue probably arises for the first pattern outer half which looks like (a' + CST2) * CST3 with a' = a * CST1? The appropriate solution might be to perform the arithmetic in an unsigned type with the implication that has on value-range analysis. Richard. > + > /* Optimize A / A to 1.0 if we don't care about > NaNs or Infinities. */ > (simplify > diff --git a/gcc/testsuite/gcc.dg/vect/slp-11a.c b/gcc/testsuite/gcc.dg/vect/slp-11a.c > index bcd3c861ca4..e6632fa77be 100644 > --- a/gcc/testsuite/gcc.dg/vect/slp-11a.c > +++ b/gcc/testsuite/gcc.dg/vect/slp-11a.c > @@ -9,14 +9,14 @@ int > main1 () > { > int i; > - unsigned int out[N*8], a0, a1, a2, a3, a4, a5, a6, a7, b1, b0, b2, b3, b4, b5, b6, b7; > - unsigned int in[N*8] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63}; > + int out[N*8], a0, a1, a2, a3, a4, a5, a6, a7, b1, b0, b2, b3, b4, b5, b6, b7; > + int in[N*8] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63}; > > /* Different operations - not SLPable. */ > for (i = 0; i < N; i++) > { > a0 = in[i*8] + 5; > - a1 = in[i*8 + 1] * 6; > + a1 = in[i*8 + 1] * 51072; > a2 = in[i*8 + 2] + 7; > a3 = in[i*8 + 3] + 8; > a4 = in[i*8 + 4] + 9; > @@ -25,7 +25,7 @@ main1 () > a7 = in[i*8 + 7] + 12; > > b0 = a0 * 3; > - b1 = a1 * 2; > + b1 = a1 * 51072; > b2 = a2 * 12; > b3 = a3 * 5; > b4 = a4 * 8; > @@ -47,7 +47,7 @@ main1 () > for (i = 0; i < N; i++) > { > if (out[i*8] != (in[i*8] + 5) * 3 - 2 > - || out[i*8 + 1] != (in[i*8 + 1] * 6) * 2 - 3 > + || out[i*8 + 1] != (in[i*8 + 1] * 51072) * 51072 - 3 > || out[i*8 + 2] != (in[i*8 + 2] + 7) * 12 - 2 > || out[i*8 + 3] != (in[i*8 + 3] + 8) * 5 - 1 > || out[i*8 + 4] != (in[i*8 + 4] + 9) * 8 - 8 > diff --git a/gcc/testsuite/gcc.target/i386/pr53533-1.c b/gcc/testsuite/gcc.target/i386/pr53533-1.c > new file mode 100644 > index 00000000000..095de665366 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr53533-1.c > @@ -0,0 +1,23 @@ > +/* { dg-do compile } */ > +/* { dg-options "-O1" } */ > +/* { dg-final { scan-assembler-times "imull\[ \t\]" "1" } } */ > +/* { dg-final { scan-assembler-times "(?:addl|subl)\[ \t\]" "1" { target { ! ia32 } } } } */ > + > +void > +__attribute__((noipa)) > +foo (unsigned a[256], unsigned b[256]) > +{ > + int i; > + for (i = 0; i < 256; ++i) > + { > + unsigned tmp = a[i] + 12345U; > + tmp *= 914237U; > + tmp += 12332U; > + tmp *= 914237U; > + tmp += 12332U; > + tmp *= 914237U; > + tmp -= 13U; > + tmp *= 8000U; > + b[i] = tmp; > + } > +} > diff --git a/gcc/testsuite/gcc.target/i386/pr53533-2.c b/gcc/testsuite/gcc.target/i386/pr53533-2.c > new file mode 100644 > index 00000000000..c31b6ff4dec > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr53533-2.c > @@ -0,0 +1,46 @@ > +/* { dg-do run } */ > +/* { dg-options "-O2" } */ > + > +#include "pr53533-1.c" > + > +void > +__attribute__((optimize("-O0"))) > +foo1 (unsigned a[256], unsigned b[256]) > +{ > + int i; > + for (i = 0; i < 256; ++i) > + { > + unsigned tmp = a[i] + 12345U; > + tmp *= 914237U; > + tmp += 12332U; > + tmp *= 914237U; > + tmp += 12332U; > + tmp *= 914237U; > + tmp -= 13U; > + tmp *= 8000U; > + b[i] = tmp; > + } > +} > + > +int main() > +{ > + unsigned int a[256]; > + unsigned int b[256]; > + unsigned int c[256]; > + for (unsigned int i = 0; i != 256; i++) > + { > + b[i] = 0; > + c[i] = 1; > + a[i] = i * i - 10 * i + 33; > + } > + foo (a, b); > + foo1 (a, c); > + > + for (unsigned int i = 0; i != 256; i++) > + { > + if (b[i] != c[i]) > + __builtin_abort (); > + } > + > + return 0; > +} > diff --git a/gcc/testsuite/gcc.target/i386/pr53533-3.c b/gcc/testsuite/gcc.target/i386/pr53533-3.c > new file mode 100644 > index 00000000000..3b260d134e9 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr53533-3.c > @@ -0,0 +1,24 @@ > +/* { dg-do compile } */ > +/* { dg-options "-O1 -fwrapv" } */ > +/* { dg-final { scan-assembler-times "imull\[ \t\]" "1" } } */ > +/* { dg-final { scan-assembler-times "(?:addl|subl)\[ \t\]" "1" { target { ! ia32 } } } } */ > + > +void > +__attribute__((noipa)) > +foo (int a[256], int b[256]) > +{ > + int i; > + for (i = 0; i < 256; ++i) > + { > + int tmp = a[i] + 12345; > + tmp *= 914237; > + tmp += 12332; > + tmp *= 914237; > + tmp += 12332; > + tmp *= 914237; > + tmp -= 13; > + tmp *= 8000; > + b[i] = tmp; > + } > +} > + > diff --git a/gcc/testsuite/gcc.target/i386/pr53533-4.c b/gcc/testsuite/gcc.target/i386/pr53533-4.c > new file mode 100644 > index 00000000000..c29f90a44dc > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr53533-4.c > @@ -0,0 +1,46 @@ > +/* { dg-do run } */ > +/* { dg-options "-O2 -fwrapv" } */ > + > +#include "pr53533-3.c" > + > +void > +__attribute__((optimize("-O0"))) > +foo1 (int a[256], int b[256]) > +{ > + int i; > + for (i = 0; i < 256; ++i) > + { > + int tmp = a[i] + 12345; > + tmp *= 914237; > + tmp += 12332; > + tmp *= 914237; > + tmp += 12332; > + tmp *= 914237; > + tmp -= 13; > + tmp *= 8000; > + b[i] = tmp; > + } > +} > + > +int main() > +{ > + int a[256]; > + int b[256]; > + int c[256]; > + for (int i = 0; i != 256; i++) > + { > + b[i] = 0; > + c[i] = 1; > + a[i] = i * i - 10 * i + 33; > + } > + foo (a, b); > + foo1 (a, c); > + > + for (unsigned int i = 0; i != 256; i++) > + { > + if (b[i] != c[i]) > + __builtin_abort (); > + } > + > + return 0; > +} > -- > 2.18.1 >