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 [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 438533858C2B for ; Tue, 24 Oct 2023 16:18:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 438533858C2B 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 438533858C2B Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1698164333; cv=none; b=KhMHQa+6E+7p9s/0SzvRRetpwWYI0tpuKbBbBQkatsvt8sUkY4yX4thmRkdUq9vYoMAMQKPyZ0hj3Y/sU+I+MjS12IVCj0tr2+aMb2y1hFBdlcp0PT+ZGLh500Wv7AmwekYGw4A//J309nBTK6Dp8xmxmpjGG0aZj0n5BoldqmU= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1698164333; c=relaxed/simple; bh=TMRmgjyOr/jvsrbezan64CzDO7jnFZOV81f2fg1IbaM=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=O7rKUCEPAXLMgYJBOfG3e0zVNbq5xIeEs1CpkTw8jPu7CruknBcAgwCl3xMDLQUu0MIIkzAZ4L3Y+Szllmc3gSTH8347XdYOCwivCh7qkpVjIdpL0qqEimgJBF9nOnJMfgtpKOxyC43AkORt+bBtiR/l8rlMaa43Ng38prHTJ+U= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1698164330; 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=AEs8/X/NRTdOmKpbB/wWKS/gzi1YbG3YAcrSKsUmYzM=; b=b+Rhl/B7abo3daqm71Z4nKB1uKL6ng/3iknjieO/HTB1mfhycj8nOwj/EN67xsXdx5+pS6 2PHKuVrjGNOTRid9j6Qwaz/papTrS+8HirZQijdu5PmMr7lXoEDUOvY4KcD9uiPyDxAAyM OZe8wth7rksJCvsKt7n67+pp9TqCyLQ= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-425-rcUASASbOgKweu-3EEhpTA-1; Tue, 24 Oct 2023 12:18:49 -0400 X-MC-Unique: rcUASASbOgKweu-3EEhpTA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (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 4364F383DC5E for ; Tue, 24 Oct 2023 16:18:49 +0000 (UTC) Received: from pdp-11.lan (unknown [10.22.33.128]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1EB9D40C6F79; Tue, 24 Oct 2023 16:18:49 +0000 (UTC) From: Marek Polacek To: Jason Merrill , GCC Patches Subject: [PATCH] c++: error with bit-fields and scoped enums [PR111895] Date: Tue, 24 Oct 2023 12:18:43 -0400 Message-ID: <20231024161843.20031-1-polacek@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII"; x-default=true X-Spam-Status: No, score=-12.3 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 List-Id: Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? -- >8 -- Here we issue a bogus error: invalid operands of types 'unsigned char:2' and 'int' to binary 'operator!=' when casting a bit-field of scoped enum type to bool. In build_static_cast_1, perform_direct_initialization_if_possible returns NULL_TREE, because the invented declaration T t(e) fails, which is correct. So we go down to ocp_convert, which has code to deal with this case: /* We can't implicitly convert a scoped enum to bool, so convert to the underlying type first. */ if (SCOPED_ENUM_P (intype) && (convtype & CONV_STATIC)) e = build_nop (ENUM_UNDERLYING_TYPE (intype), e); but the SCOPED_ENUM_P is false since intype is . This could be fixed by using unlowered_expr_type. But then c_common_truthvalue_conversion/CASE_CONVERT has a similar problem, and unlowered_expr_type is a C++-only function. Rather than adding a dummy unlowered_expr_type to C, I think we should follow [expr.static.cast]p3: "the lvalue-to-rvalue conversion is applied to the bit-field and the resulting prvalue is used as the operand of the static_cast." There are no prvalue bit-fields, so the l-to-r conversion will get us an expression whose type is the enum. (I thought we didn't need decay_conversion because that does a whole lot more but using it would make sense to me too.) PR c++/111895 gcc/cp/ChangeLog: * typeck.cc (build_static_cast_1): Call convert_bitfield_to_declared_type. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/scoped_enum12.C: New test. --- gcc/cp/typeck.cc | 9 +++++++++ gcc/testsuite/g++.dg/cpp0x/scoped_enum12.C | 8 ++++++++ 2 files changed, 17 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp0x/scoped_enum12.C diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc index f3dc80c40cf..50427090e5d 100644 --- a/gcc/cp/typeck.cc +++ b/gcc/cp/typeck.cc @@ -8405,6 +8405,15 @@ build_static_cast_1 (location_t loc, tree type, tree expr, bool c_cast_p, return expr; if (TREE_CODE (expr) == EXCESS_PRECISION_EXPR) expr = TREE_OPERAND (expr, 0); + /* [expr.static.cast]: "If the value is not a bit-field, the result + refers to the object or the specified base class subobject thereof; + otherwise, the lvalue-to-rvalue conversion is applied to the + bit-field and the resulting prvalue is used as the operand of the + static_cast." There are no prvalue bit-fields; the l-to-r conversion + will give us an object of the underlying type of the bit-field. We + can let convert_bitfield_to_declared_type convert EXPR to the desired + type. */ + expr = convert_bitfield_to_declared_type (expr); return ocp_convert (type, expr, CONV_C_CAST, LOOKUP_NORMAL, complain); } diff --git a/gcc/testsuite/g++.dg/cpp0x/scoped_enum12.C b/gcc/testsuite/g++.dg/cpp0x/scoped_enum12.C new file mode 100644 index 00000000000..1d10431e6dc --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/scoped_enum12.C @@ -0,0 +1,8 @@ +// PR c++/111895 +// { dg-do compile { target c++11 } } + +enum class o_field : unsigned char { no, yes, different_from_s }; +struct fields { + o_field o : 2; +}; +bool func(fields f) { return static_cast(f.o); } base-commit: 99a6c1065de2db04d0f56f4b2cc89acecf21b72e -- 2.41.0