From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 9DFE63858D37 for ; Thu, 2 Mar 2023 16:36:53 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 9DFE63858D37 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677775013; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Av7hvHs192/29gaWOoL5u7ogZOOv26d05wyYzTL7rMY=; b=agzGjc94OSxx44FOChNlXy/JpKrxBuW5WA0/aa23ZQN4IAeysSz+6e4VrCkPZgij229ryp mqIW8rS0xgx9WffaS8ZY6cQVfBOZh0j4Va+H43vT777yw8wf6GEUsG8s0cUnw9pxp99wIb 0aVngSISJPkDWvk+kSkCt58UmP2ErtU= Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-142-7JfONQN_O3GFo-Ni3MN8Jg-1; Thu, 02 Mar 2023 11:36:50 -0500 X-MC-Unique: 7JfONQN_O3GFo-Ni3MN8Jg-1 Received: by mail-qk1-f198.google.com with SMTP id q25-20020a37f719000000b00742bfdd63ecso6813708qkj.4 for ; Thu, 02 Mar 2023 08:36:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677775010; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Av7hvHs192/29gaWOoL5u7ogZOOv26d05wyYzTL7rMY=; b=pr+GtHv0HyWvWms5pH721EdvB2KkeukpwDtQDzOEOnT/MsGdwwSG13Jn7FmnEwAuu3 FzXIteItEAO8USfzDeQLBVreiNI9Nvj/9ujyVFZoq9IFUqz22Tht51qPQrpa0X32RTEB upk/gI1dj8A9vGBkaUdrxmHJl5hVanmFHVhM1gGAOItwl7NDj6/6b63n0ntJFeJA9kzj 4Oi9o8RiLdOyCF8RKRlfVqILOWapNEMHLKw0a4ICKQ19UyfQhBMaMl0rSOeIEiy4odSV oEe4znh0LGFK1oasxPsE5YKT+peY0s2hTIymMJrbvflMGwOcx8hcxofKFJ0QMf9XsNIH 20lg== X-Gm-Message-State: AO0yUKVLRgYK9nx6cRWaPz3Zp/rbjNmC2+s71c4dJLZvQezCs7jZIFY0 fBp0bKkUtoTziz8IArR5yojsyYC3pfCOkLDEN7Xbpr9cF49SxyZPX46TB2nhYRPyPyDCxKS1xLX xA0zbNgYi8lelOLdCKJgasZg= X-Received: by 2002:a05:622a:1101:b0:3bf:ca04:3bc6 with SMTP id e1-20020a05622a110100b003bfca043bc6mr18216199qty.9.1677775009679; Thu, 02 Mar 2023 08:36:49 -0800 (PST) X-Google-Smtp-Source: AK7set+eHJwadtT96XS7q5UMbNKoJESHqaa6uFavTA8Uy5NMcDzl5cesVf7sq1kE1fkFsPHxAWlcbQ== X-Received: by 2002:a05:622a:1101:b0:3bf:ca04:3bc6 with SMTP id e1-20020a05622a110100b003bfca043bc6mr18216147qty.9.1677775009102; Thu, 02 Mar 2023 08:36:49 -0800 (PST) Received: from [192.168.1.108] (130-44-159-43.s15913.c3-0.arl-cbr1.sbo-arl.ma.cable.rcncustomer.com. [130.44.159.43]) by smtp.gmail.com with ESMTPSA id b15-20020ac844cf000000b003b2d890752dsm10551813qto.88.2023.03.02.08.36.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 02 Mar 2023 08:36:48 -0800 (PST) Message-ID: <5f6b816f-e863-1949-9451-331590d53948@redhat.com> Date: Thu, 2 Mar 2023 11:36:47 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH] c++: more mce_false folding from cp_fully_fold_init [PR108243] To: Patrick Palka , gcc-patches@gcc.gnu.org References: <20230221191036.1140927-1-ppalka@redhat.com> From: Jason Merrill In-Reply-To: <20230221191036.1140927-1-ppalka@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-12.6 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,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 2/21/23 14:10, Patrick Palka wrote: > We should also fold the overall initializer passed to cp_fully_fold_init > with mce_false, which enables folding of the copy-initialization of > 'a1' in the below testcase (the initializer here is an AGGR_INIT_EXPR). > > Unfortunately this doesn't help with direct- or default-initialization > because we don't call cp_fully_fold_init in that case, and even if we > did the initializer in that case is expressed as a bare CALL_EXPR > instead of an AGGR_INIT_EXPR, which cp_fully_fold_init can't really > fold. > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for > trunk? OK. > PR c++/108243 > > gcc/cp/ChangeLog: > > * cp-gimplify.cc (cp_fully_fold): Add an internal overload that > additionally takes and propagate an mce_value parameter, and > define the existing public overload in terms of it. > (cp_fully_fold_init): Pass mce_false to cp_fully_fold. > > gcc/testsuite/ChangeLog: > > * g++.dg/opt/is_constant_evaluated3.C: New test. > --- > gcc/cp/cp-gimplify.cc | 14 +++++++---- > .../g++.dg/opt/is_constant_evaluated3.C | 23 +++++++++++++++++++ > 2 files changed, 33 insertions(+), 4 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C > > diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc > index 32fe53521cc..5d5c6efb856 100644 > --- a/gcc/cp/cp-gimplify.cc > +++ b/gcc/cp/cp-gimplify.cc > @@ -2447,8 +2447,8 @@ cp_fold_rvalue (tree x) > > /* Perform folding on expression X. */ > > -tree > -cp_fully_fold (tree x) > +static tree > +cp_fully_fold (tree x, mce_value manifestly_const_eval) > { > if (processing_template_decl) > return x; > @@ -2456,7 +2456,7 @@ cp_fully_fold (tree x) > have to call both. */ > if (cxx_dialect >= cxx11) > { > - x = maybe_constant_value (x); > + x = maybe_constant_value (x, /*decl=*/NULL_TREE, manifestly_const_eval); > /* Sometimes we are given a CONSTRUCTOR but the call above wraps it into > a TARGET_EXPR; undo that here. */ > if (TREE_CODE (x) == TARGET_EXPR) > @@ -2469,6 +2469,12 @@ cp_fully_fold (tree x) > return cp_fold_rvalue (x); > } > > +tree > +cp_fully_fold (tree x) > +{ > + return cp_fully_fold (x, mce_unknown); > +} > + > /* Likewise, but also fold recursively, which cp_fully_fold doesn't perform > in some cases. */ > > @@ -2477,7 +2483,7 @@ cp_fully_fold_init (tree x) > { > if (processing_template_decl) > return x; > - x = cp_fully_fold (x); > + x = cp_fully_fold (x, mce_false); > cp_fold_data data (ff_mce_false); > cp_walk_tree (&x, cp_fold_r, &data, NULL); > return x; > diff --git a/gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C b/gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C > new file mode 100644 > index 00000000000..0a1e46e5638 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/opt/is_constant_evaluated3.C > @@ -0,0 +1,23 @@ > +// PR c++/108243 > +// { dg-do compile { target c++11 } } > +// { dg-additional-options "-O -fdump-tree-original" } > + > +struct A { > + constexpr A(int n) : n(n), m(__builtin_is_constant_evaluated()) { } > + constexpr A() : A(42) { } > + int n, m; > +}; > + > +int main() { > + A a1 = {42}; > + A a2{42}; > + A a3(42); > + A a4; > + A a5{}; > +} > + > +// { dg-final { scan-tree-dump "a1 = {\\.n=42, \\.m=0}" "original" } } > +// { dg-final { scan-tree-dump "a2 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } } > +// { dg-final { scan-tree-dump "a3 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } } > +// { dg-final { scan-tree-dump "a4 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } } > +// { dg-final { scan-tree-dump "a5 = {\\.n=42, \\.m=0}" "original" { xfail *-*-* } } }