From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by sourceware.org (Postfix) with ESMTPS id 996463858C27 for ; Wed, 15 Jun 2022 06:20:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 996463858C27 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 25F4CVjT026142; Wed, 15 Jun 2022 06:20:48 GMT Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3gpp6j8s63-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Jun 2022 06:20:47 +0000 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 25F6Kjx8032626; Wed, 15 Jun 2022 06:20:45 GMT Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by ppma03ams.nl.ibm.com with ESMTP id 3gmjp9dbn8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Jun 2022 06:20:45 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 25F6KhaA18285034 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 15 Jun 2022 06:20:43 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 195D3AE053; Wed, 15 Jun 2022 06:20:43 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8777DAE04D; Wed, 15 Jun 2022 06:20:41 +0000 (GMT) Received: from [9.200.42.225] (unknown [9.200.42.225]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 15 Jun 2022 06:20:41 +0000 (GMT) Message-ID: <77f90ce9-8c36-e442-03b6-82d5450da2a1@linux.ibm.com> Date: Wed, 15 Jun 2022 14:20:39 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCH] predict: Adjust optimize_function_for_size_p [PR105818] Content-Language: en-US To: Jan Hubicka Cc: GCC Patches , Richard Sandiford , Segher Boessenkool References: <23b4998b-bbe6-b052-d7f5-5304ee0f46a3@linux.ibm.com> From: "Kewen.Lin" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: HWyFBuZszei0JNKu1-PPDOBZjXItpDbI X-Proofpoint-ORIG-GUID: HWyFBuZszei0JNKu1-PPDOBZjXItpDbI X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.517,FMLib:17.11.64.514 definitions=2022-06-15_02,2022-06-13_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 bulkscore=0 lowpriorityscore=0 priorityscore=1501 clxscore=1011 adultscore=0 mlxlogscore=999 malwarescore=0 spamscore=0 phishscore=0 suspectscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2204290000 definitions=main-2206150020 X-Spam-Status: No, score=-12.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, NICE_REPLY_A, RCVD_IN_MSPIKE_H2, 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: Wed, 15 Jun 2022 06:20:53 -0000 Hi Honza, Thanks for the comments! Some replies are inlined below. on 2022/6/14 19:37, Jan Hubicka wrote: >> Hi, >> >> Function optimize_function_for_size_p returns OPTIMIZE_SIZE_NO >> if func->decl is not null but no cgraph node is available for it. >> As PR105818 shows, this could give unexpected result. For the >> case in PR105818, when parsing bar decl in function foo, the cfun >> is a function structure for foo, for which there is none cgraph >> node, so it returns OPTIMIZE_SIZE_NO. But it's incorrect since >> the context is to optimize for size, the flag optimize_size is >> true. >> >> The patch is to make optimize_function_for_size_p to check >> optimize_size as what it does when func->decl is unavailable. >> >> One regression failure got exposed on aarch64-linux-gnu: >> >> PASS->FAIL: gcc.dg/guality/pr54693-2.c -Os \ >> -DPREVENT_OPTIMIZATION line 21 x == 10 - i >> >> The difference comes from the macro LOGICAL_OP_NON_SHORT_CIRCUIT >> used in function fold_range_test during c parsing, it uses >> optimize_function_for_speed_p which is equal to the invertion >> of optimize_function_for_size_p. At that time cfun->decl is valid >> but no cgraph node for it, w/o this patch function >> optimize_function_for_speed_p returns true eventually, while it >> returns false with this patch. Since the command line option -Os >> is specified, there is no reason to interpret it as "for speed". >> I think this failure is expected and adjust the test case >> accordingly. >> >> Is it ok for trunk? >> >> BR, >> Kewen >> ----- >> >> PR target/105818 >> >> gcc/ChangeLog: >> >> * predict.cc (optimize_function_for_size_p): Check optimize_size when >> func->decl is valid but its cgraph node is unavailable. >> >> gcc/testsuite/ChangeLog: >> >> * gcc.target/powerpc/pr105818.c: New test. >> * gcc.dg/guality/pr54693-2.c: Adjust for aarch64. >> --- >> gcc/predict.cc | 2 +- >> gcc/testsuite/gcc.dg/guality/pr54693-2.c | 2 +- >> gcc/testsuite/gcc.target/powerpc/pr105818.c | 9 +++++++++ >> 3 files changed, 11 insertions(+), 2 deletions(-) >> create mode 100644 gcc/testsuite/gcc.target/powerpc/pr105818.c >> >> diff --git a/gcc/predict.cc b/gcc/predict.cc >> index 5734e4c8516..6c60a973236 100644 >> --- a/gcc/predict.cc >> +++ b/gcc/predict.cc >> @@ -268,7 +268,7 @@ optimize_function_for_size_p (struct function *fun) >> cgraph_node *n = cgraph_node::get (fun->decl); >> if (n) >> return n->optimize_for_size_p (); >> - return OPTIMIZE_SIZE_NO; >> + return optimize_size ? OPTIMIZE_SIZE_MAX : OPTIMIZE_SIZE_NO; > > We could also do (opt_for_fn (cfun->decl, optimize_size) that is > probably better since one can change optimize_size with optimization > attribute. Good point, agree! > However I think in most cases we check for optimize_size early I think > we are doing something wrong, since at that time htere is no profile > available. Why exactly PR105818 hits the flag change issue? For PR105818, the reason why the flag changs is that: Firstly, the inconsistent flag is OPTION_MASK_SAVE_TOC_INDIRECT bit of rs6000_isa_flags_explicit, it's set as below: /* If we can shrink-wrap the TOC register save separately, then use -msave-toc-indirect unless explicitly disabled. */ if ((rs6000_isa_flags_explicit & OPTION_MASK_SAVE_TOC_INDIRECT) == 0 && flag_shrink_wrap_separate && optimize_function_for_speed_p (cfun)) rs6000_isa_flags |= OPTION_MASK_SAVE_TOC_INDIRECT; Initially, rs6000 initialize target_option_default_node with OPTION_MASK_SAVE_TOC_INDIRECT unset, at that time cfun is NULL and optimize_size is true. Later, when c parser handling function foo, it builds target option node as target_option_default_node in function handle_optimize_attribute, it does global option saving and verifying there as well, at that time the cfun is NULL, no issue is found. And function store_parm_decls allocates struct_function for foo then, cfun becomes function struct for foo, when c parser continues to handle the decl bar in foo, function handle_optimize_attribute works as before, tries to restore the target options at the end, it calls targetm.target_option.restore (rs6000_function_specific_restore) which calls function rs6000_option_override_internal again, at this time the cfun is not NULL while there is no cgraph node for its decl, optimize_function_for_speed_p returns true and gets the OPTION_MASK_SAVE_TOC_INDIRECT bit of flag rs6000_isa_flags set unexpectedly. It becomes inconsistent as the one saved previously. IMHO, both contexts of global and function decl foo here hold optimize_size, function optimize_function_for_speed_p should not return true anyway. btw, the aarch64 failed case also gets the unexpected result for optimize_function_for_speed_p during c parsing (fold_range_test <- ... <- c_parser_condition). IIUC, in parsing time we don't have the profile information available. BR, Kewen