From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw1-x112d.google.com (mail-yw1-x112d.google.com [IPv6:2607:f8b0:4864:20::112d]) by sourceware.org (Postfix) with ESMTPS id D815F38582B1 for ; Fri, 28 Oct 2022 05:53:36 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org D815F38582B1 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-yw1-x112d.google.com with SMTP id 00721157ae682-36cbcda2157so38351027b3.11 for ; Thu, 27 Oct 2022 22:53:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=SdeqZARPwe48LlqblZ2/8djn/kYHRTbvhhWFRaXG2DU=; b=kRCAqpo8k2u2kZgXGRCbzCb4rNM/ujgXBsk1PSTGBwQP3rMCLK4T1HZi9H/+S5ZmHw yPeIOAYmCW2cTr/byQVwpD/Ik8CErykk5Ww7yy5sCSyUP7A6zQfN7AIAhwxsof1oMM8z pqjKcJuw0z/aBUOjrI4lkKavK9bwexddv8cr3OUTCzv4/N/69swZnk/yu2u2ds9QwQZa +TRRVYaU7ZJnoN1eM8Lf1htbr5fUSgx4fTiEHWyjkoQE33DQ/sAOOCMxJVL70cTX67LH gMCS9Ij6yHi1QR9GKflawFOkY9Y9Ij+CJONQAt4LNp2Wt7AnlN4TqeOXbC4gMfUKOSk7 hiTQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=SdeqZARPwe48LlqblZ2/8djn/kYHRTbvhhWFRaXG2DU=; b=os/HSsZ+Lhl/CiCAmIpSPKriNlGZaEfJW+lmeGkc9RSdKKkbbfp06VPFp3o35sx/cc ZTCYooWNQL2ejFMNtoy/KOY06z1IpUC1Od11+bLaJko4ijr1P3V6O+V4WIxvyQGXBGvg Gh8dgUqOTdmdUbo05VJduQGcH+tp5v9ygtQClx08nhffzr7XMKmZTQlFoPhGYfqqQ4Lu rHyWDc/RxoFcT+7FyduU8SlvKW89BTCwdpL8XFKanL30ZpMkgZLXoY1JL9/JQbUniEti FVKlQ23N35ewf8Diobanw874qqbaAFFugcA7Wa1WVOFizI4qEVNXFcXcV/3bYGRp4miP zB9Q== X-Gm-Message-State: ACrzQf00r4DdRHGv1SxOOkwPTlYpaCkb1FQi9+lCg7ZpTunJJwGp9YRf BxLdZsNi4bW/dp1/uJLkpzXJujZc2ZIPgv2ZlfhWzvrSDS4= X-Google-Smtp-Source: AMsMyM7hAuTQZ/bl2LAT4a/dAkx0IjJ15wqI3CUSxWU/XEngf/UgK867gWlFHxeRQk+/vSq3ZfCemrKFJdRvg0ej6jY= X-Received: by 2002:a81:df07:0:b0:367:7b4e:f52 with SMTP id c7-20020a81df07000000b003677b4e0f52mr41657071ywn.475.1666936416153; Thu, 27 Oct 2022 22:53:36 -0700 (PDT) MIME-Version: 1.0 References: <20221026185857.234023-1-hjl.tools@gmail.com> In-Reply-To: <20221026185857.234023-1-hjl.tools@gmail.com> From: Hongtao Liu Date: Fri, 28 Oct 2022 13:56:44 +0800 Message-ID: Subject: Re: [PATCH] x86: Replace ne:CCC/ne:CCO with UNSPEC_CC_NE in neg patterns To: "H.J. Lu" Cc: gcc-patches@gcc.gnu.org, Uros Bizjak Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-7.2 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 autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Thu, Oct 27, 2022 at 2:59 AM H.J. Lu via Gcc-patches wrote: > > In i386.md, neg patterns which set MODE_CC register like > > (set (reg:CCC FLAGS_REG) > (ne:CCC (match_operand:SWI48 1 "general_reg_operand") (const_int 0))) > > can lead to errors when operand 1 is a constant value. If FLAGS_REG in > > (set (reg:CCC FLAGS_REG) > (ne:CCC (const_int 2) (const_int 0))) > > is set to 1, RTX simplifiers may simplify > > (set (reg:SI 93) > (neg:SI (ltu:SI (reg:CCC 17 flags) (const_int 0 [0])))) > > as > > (set (reg:SI 93) > (neg:SI (ltu:SI (const_int 1) (const_int 0 [0])))) > > which leads to incorrect results since LTU on MODE_CC register isn't the > same as "unsigned less than" in x86 backend. To prevent RTL optimizers > from setting MODE_CC register to a constant, use UNSPEC_CC_NE to replace > ne:CCC/ne:CCO when setting FLAGS_REG in neg patterns. > > gcc/ > > PR target/107172 > * config/i386/i386.md (UNSPEC_CC_NE): New. > Replace ne:CCC/ne:CCO with UNSPEC_CC_NE in neg patterns. > > gcc/testsuite/ > > PR target/107172 > * gcc.target/i386/pr107172.c: New test. > --- > gcc/config/i386/i386.md | 45 +++++++++++++----------- > gcc/testsuite/gcc.target/i386/pr107172.c | 26 ++++++++++++++ > 2 files changed, 51 insertions(+), 20 deletions(-) > create mode 100644 gcc/testsuite/gcc.target/i386/pr107172.c > > diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md > index baf1f1f8fa2..aaa678e7314 100644 > --- a/gcc/config/i386/i386.md > +++ b/gcc/config/i386/i386.md > @@ -113,6 +113,7 @@ (define_c_enum "unspec" [ > UNSPEC_PEEPSIB > UNSPEC_INSN_FALSE_DEP > UNSPEC_SBB > + UNSPEC_CC_NE > > ;; For SSE/MMX support: > UNSPEC_FIX_NOTRUNC > @@ -11470,7 +11471,7 @@ (define_insn_and_split "*neg2_doubleword" > "&& reload_completed" > [(parallel > [(set (reg:CCC FLAGS_REG) > - (ne:CCC (match_dup 1) (const_int 0))) > + (unspec:CCC [(match_dup 1) (const_int 0)] UNSPEC_CC_NE)) > (set (match_dup 0) (neg:DWIH (match_dup 1)))]) > (parallel > [(set (match_dup 2) > @@ -11499,7 +11500,8 @@ (define_peephole2 > (match_operand:SWI48 1 "nonimmediate_gr_operand")) > (parallel > [(set (reg:CCC FLAGS_REG) > - (ne:CCC (match_operand:SWI48 2 "general_reg_operand") (const_int 0))) > + (unspec:CCC [(match_operand:SWI48 2 "general_reg_operand") > + (const_int 0)] UNSPEC_CC_NE)) > (set (match_dup 2) (neg:SWI48 (match_dup 2)))]) > (parallel > [(set (match_dup 0) > @@ -11517,7 +11519,7 @@ (define_peephole2 > && !reg_mentioned_p (operands[2], operands[1])" > [(parallel > [(set (reg:CCC FLAGS_REG) > - (ne:CCC (match_dup 2) (const_int 0))) > + (unspec:CCC [(match_dup 2) (const_int 0)] UNSPEC_CC_NE)) > (set (match_dup 2) (neg:SWI48 (match_dup 2)))]) > (parallel > [(set (match_dup 0) > @@ -11543,7 +11545,8 @@ (define_peephole2 > (clobber (reg:CC FLAGS_REG))]) > (parallel > [(set (reg:CCC FLAGS_REG) > - (ne:CCC (match_operand:SWI48 1 "general_reg_operand") (const_int 0))) > + (unspec:CCC [(match_operand:SWI48 1 "general_reg_operand") > + (const_int 0)] UNSPEC_CC_NE)) > (set (match_dup 1) (neg:SWI48 (match_dup 1)))]) > (parallel > [(set (match_dup 0) > @@ -11559,7 +11562,7 @@ (define_peephole2 > "REGNO (operands[0]) != REGNO (operands[1])" > [(parallel > [(set (reg:CCC FLAGS_REG) > - (ne:CCC (match_dup 1) (const_int 0))) > + (unspec:CCC [(match_dup 1) (const_int 0)] UNSPEC_CC_NE)) > (set (match_dup 1) (neg:SWI48 (match_dup 1)))]) > (parallel > [(set (match_dup 0) > @@ -11635,9 +11638,9 @@ (define_insn "*negsi_2_zext" > > (define_insn "*neg_ccc_1" > [(set (reg:CCC FLAGS_REG) > - (ne:CCC > - (match_operand:SWI 1 "nonimmediate_operand" "0") > - (const_int 0))) > + (unspec:CCC > + [(match_operand:SWI 1 "nonimmediate_operand" "0") > + (const_int 0)] UNSPEC_CC_NE)) > (set (match_operand:SWI 0 "nonimmediate_operand" "=m") > (neg:SWI (match_dup 1)))] > "" > @@ -11647,9 +11650,9 @@ (define_insn "*neg_ccc_1" > > (define_insn "*neg_ccc_2" > [(set (reg:CCC FLAGS_REG) > - (ne:CCC > - (match_operand:SWI 1 "nonimmediate_operand" "0") > - (const_int 0))) > + (unspec:CCC > + [(match_operand:SWI 1 "nonimmediate_operand" "0") > + (const_int 0)] UNSPEC_CC_NE)) > (clobber (match_scratch:SWI 0 "="))] > "" > "neg{}\t%0" > @@ -11659,8 +11662,8 @@ (define_insn "*neg_ccc_2" > (define_expand "x86_neg_ccc" > [(parallel > [(set (reg:CCC FLAGS_REG) > - (ne:CCC (match_operand:SWI48 1 "register_operand") > - (const_int 0))) > + (unspec:CCC [(match_operand:SWI48 1 "register_operand") > + (const_int 0)] UNSPEC_CC_NE)) > (set (match_operand:SWI48 0 "register_operand") > (neg:SWI48 (match_dup 1)))])]) > > @@ -11686,8 +11689,9 @@ (define_insn "*negqi_ext_2" > ;; Negate with jump on overflow. > (define_expand "negv3" > [(parallel [(set (reg:CCO FLAGS_REG) > - (ne:CCO (match_operand:SWI 1 "register_operand") > - (match_dup 3))) > + (unspec:CCO > + [(match_operand:SWI 1 "register_operand") > + (match_dup 3)] UNSPEC_CC_NE)) > (set (match_operand:SWI 0 "register_operand") > (neg:SWI (match_dup 1)))]) > (set (pc) (if_then_else > @@ -11703,8 +11707,9 @@ (define_expand "negv3" > > (define_insn "*negv3" > [(set (reg:CCO FLAGS_REG) > - (ne:CCO (match_operand:SWI 1 "nonimmediate_operand" "0") > - (match_operand:SWI 2 "const_int_operand"))) > + (unspec:CCO [(match_operand:SWI 1 "nonimmediate_operand" "0") > + (match_operand:SWI 2 "const_int_operand")] > + UNSPEC_CC_NE)) > (set (match_operand:SWI 0 "nonimmediate_operand" "=m") > (neg:SWI (match_dup 1)))] > "ix86_unary_operator_ok (NEG, mode, operands) > @@ -11770,7 +11775,7 @@ (define_insn_and_split "*abs2_doubleword" > "&& 1" > [(parallel > [(set (reg:CCC FLAGS_REG) > - (ne:CCC (match_dup 1) (const_int 0))) > + (unspec:CCC [(match_dup 1) (const_int 0)] UNSPEC_CC_NE)) > (set (match_dup 2) (neg:DWIH (match_dup 1)))]) > (parallel > [(set (match_dup 5) > @@ -11814,7 +11819,7 @@ (define_insn_and_split "*nabs2_doubleword" > "&& 1" > [(parallel > [(set (reg:CCC FLAGS_REG) > - (ne:CCC (match_dup 1) (const_int 0))) > + (unspec:CCC [(match_dup 1) (const_int 0)] UNSPEC_CC_NE)) > (set (match_dup 2) (neg:DWIH (match_dup 1)))]) > (parallel > [(set (match_dup 5) > @@ -21456,7 +21461,7 @@ (define_split > (const_int 0))))] > "" > [(set (reg:CCC FLAGS_REG) > - (ne:CCC (match_dup 1) (const_int 0))) > + (unspec:CCC [(match_dup 1) (const_int 0)] UNSPEC_CC_NE)) Do we have a define_insn for this? It looks like a setcc to me. > (set (match_dup 0) > (neg:SWI (ltu:SWI (reg:CCC FLAGS_REG) (const_int 0))))]) > > diff --git a/gcc/testsuite/gcc.target/i386/pr107172.c b/gcc/testsuite/gcc.target/i386/pr107172.c > new file mode 100644 > index 00000000000..d2c85f3f47c > --- /dev/null > +++ b/gcc/testsuite/gcc.target/i386/pr107172.c > @@ -0,0 +1,26 @@ > +/* { dg-do run } */ > +/* { dg-options "-O1 -ftree-vrp" } */ > + > +int a, c, d; > +int > +main() > +{ > + long e = 1; > + int f = a = 1; > +L1: > + if (a) > + a = 2; > + int h = e = ~e; > + c = -1; > + if (e >= a) > + goto L2; > + if (-1 > a) > + goto L1; > + if (a) > + f = -1; > +L2: > + d = (-f + d) & h; > + if (d) > + __builtin_abort(); > + return 0; > +} > -- > 2.37.3 > -- BR, Hongtao