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 4D2E43850B0A for ; Sat, 10 Dec 2022 09:33:55 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 4D2E43850B0A 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=1670664835; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type; bh=k5KlE2VlZpt4az2x1BHS82ppYaLM4lWVY1dHpmEV+o0=; b=hwtZiBnHdOFtX+QuKOgt3iPEc9PrbmjEMKcPQUL5dYCFu5acJuWA5JoIJ3FQkR4j0rqJQ4 sj2SPi3SV2SSBpBkb88NUxltiB8aZcuL1t8DOSuf8HTm3i/Zc3J3BHJNnRoGFEhvrM5uov m+HOwNreThbtRDkm8TEW0LlgFP3Gkcg= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-70-ZFsjQPRaORmTXCek2qSuMQ-1; Sat, 10 Dec 2022 04:33:52 -0500 X-MC-Unique: ZFsjQPRaORmTXCek2qSuMQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D9B303C01D9E for ; Sat, 10 Dec 2022 09:33:51 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.195.114]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 949E8C15BA8; Sat, 10 Dec 2022 09:33:51 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 2BA9XkJG3888013 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Sat, 10 Dec 2022 10:33:47 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 2BA9Xkrb3888012; Sat, 10 Dec 2022 10:33:46 +0100 Date: Sat, 10 Dec 2022 10:33:46 +0100 From: Jakub Jelinek To: Jason Merrill Cc: gcc-patches@gcc.gnu.org Subject: [PATCH] c++: Ensure !!var is not an lvalue [PR107065] Message-ID: Reply-To: Jakub Jelinek MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-3.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,KAM_TRUTHINESS,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Hi! The TRUTH_NOT_EXPR case in cp_build_unary_op is one of the spots where we somewhat fold immediately using invert_truthvalue_loc. I've tried using return build1_loc (location, TRUTH_NOT_EXPR, boolean_type_node, arg); in there instead, but unfortunately that regressed Wlogical-not-parentheses-*.c pr49706.c pr62199.c pr65120.c sequence-pt-1.C tests, so at least for backporting that doesn't seem to be a way to go. So, this patch instead wraps it into NON_LVALUE_EXPR if needed (which also need a tweak for some tests in the pr47906.c test, but nothing major), with the intent to make it backportable, and later I'll try to do further steps to avoid folding here prematurely. Most of the problems with build1 TRUTH_NOT_EXPR are that it doesn't even invert comparisons as most common case and lots of warning code isn't able to deal with ! around comparisons; so perhaps one way to do this would be fold by hand only invertable comparisons and for the rest create TRUTH_NOT_EXPR. Anyway, bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk (for now) and for release branches (after a while on the trunk)? 2022-12-10 Jakub Jelinek PR c++/107065 gcc/cp/ * typeck.cc (cp_build_unary_op) : If invert_truthvalue_loc returns obvalue_p, wrap it into NON_LVALUE_EXPR. * parser.cc (cp_parser_binary_expression): Don't call warn_logical_not_parentheses if current.lhs is a NON_LVALUE_EXPR of a decl with boolean type. gcc/testsuite/ * g++.dg/cpp0x/pr107065.C: New test. --- gcc/cp/typeck.cc.jj 2022-11-30 10:29:42.024701797 +0100 +++ gcc/cp/typeck.cc 2022-12-09 17:47:54.132856233 +0100 @@ -7396,9 +7396,13 @@ cp_build_unary_op (enum tree_code code, build_zero_cst (TREE_TYPE (arg)), complain); arg = perform_implicit_conversion (boolean_type_node, arg, complain); - val = invert_truthvalue_loc (location, arg); if (arg != error_mark_node) - return val; + { + val = invert_truthvalue_loc (location, arg); + if (obvalue_p (val)) + val = non_lvalue_loc (location, val); + return val; + } errstring = _("in argument to unary !"); break; --- gcc/cp/parser.cc.jj 2022-12-09 11:02:35.871444993 +0100 +++ gcc/cp/parser.cc 2022-12-09 19:14:26.698847734 +0100 @@ -10224,7 +10224,10 @@ cp_parser_binary_expression (cp_parser* || (TREE_CODE (TREE_TYPE (TREE_OPERAND (current.lhs, 0))) != BOOLEAN_TYPE)))) /* Avoid warning for !!b == y where b is boolean. */ - && (!DECL_P (tree_strip_any_location_wrapper (current.lhs)) + && (!(DECL_P (tree_strip_any_location_wrapper (current.lhs)) + || (TREE_CODE (current.lhs) == NON_LVALUE_EXPR + && DECL_P (tree_strip_any_location_wrapper + (TREE_OPERAND (current.lhs, 0))))) || TREE_TYPE (current.lhs) == NULL_TREE || TREE_CODE (TREE_TYPE (current.lhs)) != BOOLEAN_TYPE)) warn_logical_not_parentheses (current.loc, current.tree_type, --- gcc/testsuite/g++.dg/cpp0x/pr107065.C.jj 2022-12-09 16:22:59.686548071 +0100 +++ gcc/testsuite/g++.dg/cpp0x/pr107065.C 2022-12-09 16:22:59.686548071 +0100 @@ -0,0 +1,14 @@ +// PR c++/107065 +// { dg-do compile { target c++11 } } + +template struct is_same { static constexpr bool value = false; }; +template struct is_same { static constexpr bool value = true; }; + +int +main () +{ + bool b = true; + static_assert (is_same::value, ""); + auto bb = (!(!b)); + static_assert (is_same::value, ""); +} Jakub