From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by sourceware.org (Postfix) with ESMTPS id DE3083846411 for ; Fri, 5 Apr 2024 18:14:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org DE3083846411 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org DE3083846411 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=2607:f8b0:4864:20::52c ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1712340854; cv=none; b=BwEL44bvxaksnYmaJ9a4NIEYoZOVMochTrg6gXMBD+33lJlV1yzB1hKSMAqPNv6CXu4RU8Nx9t21ofHW2swYbmxwt9FYxMshpOBr6UldVzKaNRrax1WyuHlXaTUQedJRzCk0VatHujCkY/C/MiQSu/dWh9ytkNDRfwBu6HnUdZs= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1712340854; c=relaxed/simple; bh=nEcWgXRgSiorxa7o0BbpH2VINSF46a+wGSKKCu1bPxY=; h=DKIM-Signature:MIME-Version:From:Date:Message-ID:Subject:To; b=YNwujzcIr2ebC2ur//O3bBZQle+yy+hKV++3uUWBRKKUW/ZHz85QZIu7TK1MYl/qvzFsg2HQeGqyRSA2a5KNxazEGYGOcW3D83hOXKFp+Hl1YicG40b0Sz++d1P6nyTWaPdve+FGaj1qnY+g9Vk6xAOvjataP2TfmJc/qBrqPXg= ARC-Authentication-Results: i=1; server2.sourceware.org Received: by mail-pg1-x52c.google.com with SMTP id 41be03b00d2f7-5d8b519e438so2015836a12.1 for ; Fri, 05 Apr 2024 11:14:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1712340851; x=1712945651; darn=gcc.gnu.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=BEFXG+l512039BbU04qcBIsTdAQcED8DL1Dg6AZLbWU=; b=Fu1L/XIp//NlqM6y5/RILB4gss23Ivg4QZ6v82lWObJWDD62FhtTbiVsImHfR246ls jdM9HgjgMK+52E1vVyGGf98HvQXdaWq0Smhq0YpEBA7Be3uSotyvEDzpxMpfNQvqy4ur X2n+AnOvVXXrLMSjBJpVEYmo7HUQfidiQJIArT/w/NrTT1YH05T/jUj5g6UxWdu7yVpp 3pKFc7nTuWMwy5bInMCaFKy6FTDtlYaX/Du4KRw2zuaNdUy9Pa9su7V20/8MY9P1trlb UcOU6QYDq7coPoE2zGQLtleds02LFWfrt+lj5pTUDhnu+j55VUhOnPCeHpXOuoHj6owY C1Sw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712340851; x=1712945651; h=content-transfer-encoding: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=BEFXG+l512039BbU04qcBIsTdAQcED8DL1Dg6AZLbWU=; b=OSR8FoQgYSTzqNh+Fa/pLGZNbcWqdtXJkZcCLHIUhjDz6vSqDlAk+ERXgH7q+5mkKh pQ6aXQ9BuYQmANz7Bkx7fscMZEqIQLTknFHD0coeV54sVzRN6ToqjUIghQdyV3HRN9KD odMlKmXTcCZvTDWqoGsLIy02B71SWNUevNWWwJUdaUS6PYfbfJ73TobOCJlrKMe2LnDo 8UNO4Iu5FKEkRpmKXZMF3dkDvnR1mllBJgaHUv6EbbHxFMCKufuAhk7m8OEG3bfz8jPQ 2/3FxSyUE+xxxR6VzKQ5fDgjCa3tlWMZkGJZ46aYpYqQYx2WyoygYvzMdvLLclqhJWof VLXw== X-Gm-Message-State: AOJu0Yytjkx22HpIZwGW5D8j3dvQ8/U7fjf34H1jmTAp2MVSRMD1G2Co 7jW9xnyvOc/yuoM1TT0bpDCfPc2SUWyXLARoAVwUz/0yhL1doZKXKYwcH2aBlU9i0jITgHAKjmJ u8+GWSy7s8pTUGlJn33djCNUxugIVIhl1 X-Google-Smtp-Source: AGHT+IESi/Gx36NbVf6lJD+t233J14FzH5GjD3kEx9hBcuZ7W/1qtvwAzD//BPDaVDyWeLXPBS48LbbPHrjUObPbF0w= X-Received: by 2002:a17:90a:df15:b0:29f:ce37:50d8 with SMTP id gp21-20020a17090adf1500b0029fce3750d8mr1922239pjb.17.1712340850789; Fri, 05 Apr 2024 11:14:10 -0700 (PDT) MIME-Version: 1.0 References: <20240405122625.847311-1-manolis.tsamis@vrull.eu> In-Reply-To: <20240405122625.847311-1-manolis.tsamis@vrull.eu> From: Andrew Pinski Date: Fri, 5 Apr 2024 11:13:59 -0700 Message-ID: Subject: Re: [PATCH] Add extra copy of the ifcombine pass after pre [PR102793] To: Manolis Tsamis Cc: gcc-patches@gcc.gnu.org, Andrew Pinski , Philipp Tomsich , Tamar Christina , Jiangning Liu Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-7.8 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 Fri, Apr 5, 2024 at 5:28=E2=80=AFAM Manolis Tsamis wrote: > > If we consider code like: > > if (bar1 =3D=3D x) > return foo(); > if (bar2 !=3D y) > return foo(); > return 0; > > We would like the ifcombine pass to convert this to: > > if (bar1 =3D=3D x || bar2 !=3D y) > return foo(); > return 0; > > The ifcombine pass can handle this transformation but it is ran very earl= y and > it misses the opportunity because there are two seperate blocks for foo()= . > The pre pass is good at removing duplicate code and blocks and due to tha= t > running ifcombine again after it can increase the number of successful > conversions. I do think we should have something similar to re-running ssa-ifcombine but I think it should be much later, like after the loop optimizations are done. Maybe just a simplified version of it (that does the combining and not the optimizations part) included in isel or pass_optimize_widening_mul (which itself should most likely become part of isel or renamed since it handles more than just widening multiply these days). Thanks, Andrew Pinski > > PR 102793 > > gcc/ChangeLog: > > * common.opt: -ftree-ifcombine option, enabled by default. > * doc/invoke.texi: Document. > * passes.def: Re-run ssa-ifcombine after pre. > * tree-ssa-ifcombine.cc: Make ifcombine cloneable. Add gate funct= ion. > > gcc/testsuite/ChangeLog: > > * gcc.dg/tree-ssa/20030922-2.c: Change flag to -fno-tree-ifcombin= e. > * gcc.dg/uninit-pred-6_c.c: Remove inconsistent check. > * gcc.target/aarch64/pr102793.c: New test. > > Signed-off-by: Manolis Tsamis > --- > > gcc/common.opt | 4 +++ > gcc/doc/invoke.texi | 5 ++++ > gcc/passes.def | 1 + > gcc/testsuite/gcc.dg/tree-ssa/20030922-2.c | 2 +- > gcc/testsuite/gcc.dg/uninit-pred-6_c.c | 4 --- > gcc/testsuite/gcc.target/aarch64/pr102793.c | 30 +++++++++++++++++++++ > gcc/tree-ssa-ifcombine.cc | 5 ++++ > 7 files changed, 46 insertions(+), 5 deletions(-) > create mode 100644 gcc/testsuite/gcc.target/aarch64/pr102793.c > > diff --git a/gcc/common.opt b/gcc/common.opt > index ad348844775..e943202bcf1 100644 > --- a/gcc/common.opt > +++ b/gcc/common.opt > @@ -3163,6 +3163,10 @@ ftree-phiprop > Common Var(flag_tree_phiprop) Init(1) Optimization > Enable hoisting loads from conditional pointers. > > +ftree-ifcombine > +Common Var(flag_tree_ifcombine) Init(1) Optimization > +Merge some conditional branches to simplify control flow. > + > ftree-pre > Common Var(flag_tree_pre) Optimization > Enable SSA-PRE optimization on trees. > diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi > index e2edf7a6c13..8d2ff6b4512 100644 > --- a/gcc/doc/invoke.texi > +++ b/gcc/doc/invoke.texi > @@ -13454,6 +13454,11 @@ This flag is enabled by default at @option{-O1} = and higher. > Perform hoisting of loads from conditional pointers on trees. This > pass is enabled by default at @option{-O1} and higher. > > +@opindex ftree-ifcombine > +@item -ftree-ifcombine > +Merge some conditional branches to simplify control flow. This pass > +is enabled by default at @option{-O1} and higher. > + > @opindex fhoist-adjacent-loads > @item -fhoist-adjacent-loads > Speculatively hoist loads from both branches of an if-then-else if the > diff --git a/gcc/passes.def b/gcc/passes.def > index 1cbbd413097..1765b476131 100644 > --- a/gcc/passes.def > +++ b/gcc/passes.def > @@ -270,6 +270,7 @@ along with GCC; see the file COPYING3. If not see > NEXT_PASS (pass_lim); > NEXT_PASS (pass_walloca, false); > NEXT_PASS (pass_pre); > + NEXT_PASS (pass_tree_ifcombine); > NEXT_PASS (pass_sink_code, false /* unsplit edges */); > NEXT_PASS (pass_sancov); > NEXT_PASS (pass_asan); > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/20030922-2.c b/gcc/testsuite/g= cc.dg/tree-ssa/20030922-2.c > index 16c79da9521..66c9f481a2f 100644 > --- a/gcc/testsuite/gcc.dg/tree-ssa/20030922-2.c > +++ b/gcc/testsuite/gcc.dg/tree-ssa/20030922-2.c > @@ -1,5 +1,5 @@ > /* { dg-do compile } */ > -/* { dg-options "-O1 -fdump-tree-dom2 -fdisable-tree-ifcombine" } */ > +/* { dg-options "-O1 -fdump-tree-dom2 -fno-tree-ifcombine" } */ > > struct rtx_def; > typedef struct rtx_def *rtx; > diff --git a/gcc/testsuite/gcc.dg/uninit-pred-6_c.c b/gcc/testsuite/gcc.d= g/uninit-pred-6_c.c > index f60868dad23..2d8e6501a45 100644 > --- a/gcc/testsuite/gcc.dg/uninit-pred-6_c.c > +++ b/gcc/testsuite/gcc.dg/uninit-pred-6_c.c > @@ -20,10 +20,6 @@ int foo (int n, int l, int m, int r) > if ( (n > 10) && l) > blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */ > > - if (l) > - if (n > 12) > - blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */ > - > return 0; > } > > diff --git a/gcc/testsuite/gcc.target/aarch64/pr102793.c b/gcc/testsuite/= gcc.target/aarch64/pr102793.c > new file mode 100644 > index 00000000000..78d48e01637 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/aarch64/pr102793.c > @@ -0,0 +1,30 @@ > +/* { dg-do compile } */ > +/* { dg-options "-O2" } */ > + > +typedef unsigned long uint64_t; > + > +int ccmp1(uint64_t* s1, uint64_t* s2, int(*foo)(void)) > +{ > + uint64_t d1, d2, bar; > + d1 =3D *s1++; > + d2 =3D *s2++; > + bar =3D (d1 + d2) & 0xabcd; > + if (bar =3D=3D 0 || d1 !=3D d2) > + return foo(); > + return 0; > +} > + > +int ccmp2(uint64_t* s1, uint64_t* s2, int(*foo)(void)) > +{ > + uint64_t d1, d2, bar; > + d1 =3D *s1++; > + d2 =3D *s2++; > + bar =3D (d1 + d2) & 0xabcd; > + if (bar =3D=3D 0) > + return foo(); > + if (d1 !=3D d2) > + return foo(); > + return 0; > +} > + > +/* { dg-final { scan-assembler-times "ccmp\t" 2 } } */ > \ No newline at end of file > diff --git a/gcc/tree-ssa-ifcombine.cc b/gcc/tree-ssa-ifcombine.cc > index 6a3bc99190d..0bf9fe8b692 100644 > --- a/gcc/tree-ssa-ifcombine.cc > +++ b/gcc/tree-ssa-ifcombine.cc > @@ -838,6 +838,11 @@ public: > {} > > /* opt_pass methods: */ > + opt_pass * clone () final override > + { > + return new pass_tree_ifcombine (m_ctxt); > + } > + bool gate (function *) final override { return flag_tree_ifcombine; } > unsigned int execute (function *) final override; > > }; // class pass_tree_ifcombine > -- > 2.44.0 >