From patchwork Mon Apr 1 17:50:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Polacek X-Patchwork-Id: 87893 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 315CB3858407 for ; Mon, 1 Apr 2024 17:51:16 +0000 (GMT) X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org 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 112123858D20 for ; Mon, 1 Apr 2024 17:50:39 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 112123858D20 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 112123858D20 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1711993841; cv=none; b=W0H8mM/kWemFmnC2PWAnFwsZGbKJiYTaFlWNT5bNxLBqXNkDYutbehssgwa8lNyO9yh5tMPIcm3Lq6FudLWGcmtU5Q7c3NXREoxTMuOmknoUkTmQ0EvUGEV5jDMCET4zsLiGoUrbh9J98egRiUXAHmUlO7EEBphCbFPHpcLd4C0= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1711993841; c=relaxed/simple; bh=73AnkEH13H+YwjQ7R3kzUwl3RKbDaXKgCDV7KbYWBpY=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=mV4xx9D+uEXc4VOai6Ia0BoxxkAznA6tv7Lmxd9w4LWmWxzJo7vRb6a3k31kWLSJ3hZ1obaxlKQRXYfKkqNXYannofmgkIP/lRt+i88P3pGizGJZ5cjo62O80do/5B5VXMESRXTPuG8u8dX3kaqPPWRiyOL/f1nKtxksBINt+84= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1711993838; 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; bh=VVyBEv0qE0vbQ7p+ut1PYNiGaABtA3qMUmTQO86xmAc=; b=XFBbrboXJvN88f7zP0dMafaB7Jteu6BTxG8av+iIapAh42O9JMNmxdzeyUubyMKckJGPqJ sm159dGL/nW9ShaRjXubh+v7o8ZCHjx7Qy8S94JiBu7v6jFflv7tCX9HmosvIP90UEIBzX S5Rx/axVHVLYOE0AP8aBJUJFD2pnrUs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-416-BAM9G6PYPKO4ZfrpeUJxWg-1; Mon, 01 Apr 2024 13:50:37 -0400 X-MC-Unique: BAM9G6PYPKO4ZfrpeUJxWg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D0132185A784 for ; Mon, 1 Apr 2024 17:50:36 +0000 (UTC) Received: from pdp-11.lan (unknown [10.22.10.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id B31E48CED; Mon, 1 Apr 2024 17:50:36 +0000 (UTC) From: Marek Polacek To: Jason Merrill , GCC Patches Subject: [PATCH] c++: make __is_array return false for T[0] [PR114479] Date: Mon, 1 Apr 2024 13:50:34 -0400 Message-ID: <20240401175034.44681-1-polacek@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.0 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, 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 X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gcc-patches-bounces+patchwork=sourceware.org@gcc.gnu.org Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? -- >8 -- When we switched to using the __is_array built-in trait to implement std::is_array in r14-6623-g7fd9c349e45534, we started saying that T[0] is an array. There are various opinions as to whether that is the best answer, but it seems prudent to keep the GCC 13 result. PR c++/114479 gcc/cp/ChangeLog: * semantics.cc (trait_expr_value) : Return false for zero-sized arrays. gcc/testsuite/ChangeLog: * g++.dg/ext/is_array.C: Extend. --- gcc/cp/semantics.cc | 4 +++- gcc/testsuite/g++.dg/ext/is_array.C | 12 ++++++++++++ 2 files changed, 15 insertions(+), 1 deletion(-) base-commit: bba118db3f63cb1e3953a014aa3ac2ad89908950 diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc index 9838331d2a9..f561c119dfd 100644 --- a/gcc/cp/semantics.cc +++ b/gcc/cp/semantics.cc @@ -12439,7 +12439,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2) return CP_AGGREGATE_TYPE_P (type1); case CPTK_IS_ARRAY: - return type_code1 == ARRAY_TYPE; + return (type_code1 == ARRAY_TYPE + /* We don't want to report T[0] as being an array type. */ + && !(TYPE_SIZE (type1) && integer_zerop (TYPE_SIZE (type1)))); case CPTK_IS_ASSIGNABLE: return is_xible (MODIFY_EXPR, type1, type2); diff --git a/gcc/testsuite/g++.dg/ext/is_array.C b/gcc/testsuite/g++.dg/ext/is_array.C index f1a6e08b87a..84993266629 100644 --- a/gcc/testsuite/g++.dg/ext/is_array.C +++ b/gcc/testsuite/g++.dg/ext/is_array.C @@ -1,4 +1,5 @@ // { dg-do compile { target c++11 } } +// { dg-options "" } #define SA(X) static_assert((X),#X) @@ -10,18 +11,29 @@ class ClassType { }; +constexpr int sz0 = 0; +constexpr int sz2 = 2; + SA_TEST_CATEGORY(__is_array, int[2], true); SA_TEST_CATEGORY(__is_array, int[], true); +SA_TEST_CATEGORY(__is_array, int[0], false); SA_TEST_CATEGORY(__is_array, int[2][3], true); SA_TEST_CATEGORY(__is_array, int[][3], true); +SA_TEST_CATEGORY(__is_array, int[0][3], false); +SA_TEST_CATEGORY(__is_array, int[3][0], false); SA_TEST_CATEGORY(__is_array, float*[2], true); SA_TEST_CATEGORY(__is_array, float*[], true); SA_TEST_CATEGORY(__is_array, float*[2][3], true); SA_TEST_CATEGORY(__is_array, float*[][3], true); SA_TEST_CATEGORY(__is_array, ClassType[2], true); SA_TEST_CATEGORY(__is_array, ClassType[], true); +SA_TEST_CATEGORY(__is_array, ClassType[0], false); SA_TEST_CATEGORY(__is_array, ClassType[2][3], true); SA_TEST_CATEGORY(__is_array, ClassType[][3], true); +SA_TEST_CATEGORY(__is_array, ClassType[0][3], false); +SA_TEST_CATEGORY(__is_array, ClassType[2][0], false); +SA_TEST_CATEGORY(__is_array, int[sz2], true); +SA_TEST_CATEGORY(__is_array, int[sz0], false); // Sanity check. SA_TEST_CATEGORY(__is_array, ClassType, false);