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 D2E8E3858CD1 for ; Thu, 9 Nov 2023 19:33:27 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org D2E8E3858CD1 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 D2E8E3858CD1 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=1699558418; cv=none; b=GtB/6eEvsNUiDPHT2uCFeWXy4Wz4twe9DQfApiqF8eSEIou3T/1V19ZyRrnYMg+0jkBirJZnbSI7qllzEALCI/vdyBAeM9uSYdgd/35kItU2C3VE02KGrDOnHdWqs59DzxkGgfTxQC2NdNWVyUPlX0GXndxP6GcaCHrqFZoRRwA= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1699558418; c=relaxed/simple; bh=GbSi+xTSYiy6oOP13GrkwJYFs0V9ol6dZp17Pfj6w3o=; h=DKIM-Signature:MIME-Version:From:Date:Message-ID:Subject:To; b=E8jFj1OSE0oewP2rTskYy6EnvqhNFYb8KEFgaCUG+N82wfWfkjTnbZp/kO2dnjAHPy2S0ri++cV9rzE/zhfotRPHpKt6tz0wqBYPPd9BG9u/L6mj3Cwh9GV/9m+IO2TsTY4dNzaUsboxT4gQ8DXps0wpfXkRCGDy+u9tnqenSXA= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1699558407; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=XaMu/sSlzRqaqExB0YecIvUR7aBVtPrEnI+INjVjxLg=; b=G0tn+SO7RpDDS6CYR1wAXpz9FIsCRWF2uUxCjOuC95bjnCIsjcgeNVdN00NabVo9JSwjtN OoZ+J0F4RdoS+EE/cpTJOucHWTWaLO04EZQTPdtD+D6HwBcLcjZ/TDQNXmdwXV7uLo0TsM SW4jiGyBxhqY7NPjlNDoDvzcWdIG3ic= Received: from mail-yw1-f199.google.com (mail-yw1-f199.google.com [209.85.128.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-86-k4SjiucPN-COnebItPkR8w-1; Thu, 09 Nov 2023 14:33:25 -0500 X-MC-Unique: k4SjiucPN-COnebItPkR8w-1 Received: by mail-yw1-f199.google.com with SMTP id 00721157ae682-5b064442464so17074227b3.3 for ; Thu, 09 Nov 2023 11:33:25 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1699558404; x=1700163204; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=XaMu/sSlzRqaqExB0YecIvUR7aBVtPrEnI+INjVjxLg=; b=U9bQfq+vRkqwiYFxYOOdAwgnSSuf/056zvDhtE5n4AposicC8J0T+Sz9UoGWIR3k0p 9Np6SeGMgeh7Mu+HGxwSqHTe6lZke2zX+FLKBnEdm3cbZtY+vQW9D9fTiQa7z4jWQEaJ WtyXITubiNQKKZ3+q7LbEVjJvUXYFNYqH4LwFk3F9f1tZICfdiL6NXuktVVz6M2EMXSB iylbizef7ouWsp8UfEMw2znC6o6aU3lndG53Xn3pQl/E3IbIwfj2VisCpQv98jyQqb1q 2txLJB3etv1HfQUgXvDY0e0Kt3AEeK1fe+W9lJqsTMhdf4g33A8vDHseuMJh/uhMlL7k SB/A== X-Gm-Message-State: AOJu0Yw5TlAAlWs/AxkJRQTIgXTWTAGQLQ2QsKvAqn6WoYK9vVWWZNko LOhavTXdBF/i6D531Z0j4iRAl/sDxqo4WtvQyrHmV2lIJ7yLsJs4doMfx6V0CAoQ2ZWgz4qdpXw Goe0X6snPX1MK4o6+mDPIYEp5+1jPjfysCg== X-Received: by 2002:a0d:d9c9:0:b0:5a7:afcc:80fe with SMTP id b192-20020a0dd9c9000000b005a7afcc80femr6062401ywe.3.1699558404677; Thu, 09 Nov 2023 11:33:24 -0800 (PST) X-Google-Smtp-Source: AGHT+IGgBv8BFaT+VVSvdaQtbitjv8MZJw55KSiDmlI1tw5xFPCmq59ifj8MgRJgyMOhUuBT6xWqYQPQ3lV3tl4HDAA= X-Received: by 2002:a0d:d9c9:0:b0:5a7:afcc:80fe with SMTP id b192-20020a0dd9c9000000b005a7afcc80femr6062385ywe.3.1699558404428; Thu, 09 Nov 2023 11:33:24 -0800 (PST) MIME-Version: 1.0 References: <20231109160028.2829009-1-ppalka@redhat.com> In-Reply-To: <20231109160028.2829009-1-ppalka@redhat.com> From: Jonathan Wakely Date: Thu, 9 Nov 2023 19:33:13 +0000 Message-ID: Subject: Re: [PATCH] libstdc++: Fix forwarding in __take/drop_of_repeat_view [PR112453] To: Patrick Palka Cc: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-13.5 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_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE autolearn=unavailable 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 Thu, 9 Nov 2023 at 16:01, Patrick Palka wrote: > > Tested on x86_64-pc-linux-gnu, does this look OK for trunk/13? (The > && overloads are also missing on earlier branches, but I don't think > it makes a difference there since all uses of that operator* are on > lvalues before this fix.) OK for trunk and gcc-13, thanks. > > -- >8 -- > > We need to respect the value category of the repeat_view passed to these > two functions when accessing its _M_value member. This revealed that > the space-efficient partial specialization of __box lacks && overloads > of operator* to match std::optional's API. > > PR libstdc++/112453 > > libstdc++-v3/ChangeLog: > > * include/std/ranges (__detail::__box::operator*): Define && > overloads as well. > (__detail::__take_of_repeat_view): Forward __r when accessing > its _M_value member. > (__detail::__drop_of_repeat_view): Likewise. > * testsuite/std/ranges/repeat/1.cc (test07): New test. > --- > libstdc++-v3/include/std/ranges | 20 ++++++++++++++----- > libstdc++-v3/testsuite/std/ranges/repeat/1.cc | 13 ++++++++++++ > 2 files changed, 28 insertions(+), 5 deletions(-) > > diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges > index 7893e3a84c9..41f95dc8f78 100644 > --- a/libstdc++-v3/include/std/ranges > +++ b/libstdc++-v3/include/std/ranges > @@ -250,13 +250,21 @@ namespace ranges > { return true; }; > > constexpr _Tp& > - operator*() noexcept > + operator*() & noexcept > { return _M_value; } > > constexpr const _Tp& > - operator*() const noexcept > + operator*() const & noexcept > { return _M_value; } > > + constexpr _Tp&& > + operator*() && noexcept > + { return std::move(_M_value); } > + > + constexpr const _Tp&& > + operator*() const && noexcept > + { return std::move(_M_value); } > + > constexpr _Tp* > operator->() noexcept > { return std::__addressof(_M_value); } > @@ -7799,9 +7807,10 @@ namespace views::__adaptor > using _Tp = remove_cvref_t<_Range>; > static_assert(__is_repeat_view<_Tp>); > if constexpr (sized_range<_Tp>) > - return views::repeat(*__r._M_value, std::min(ranges::distance(__r), __n)); > + return views::repeat(*std::forward<_Range>(__r)._M_value, > + std::min(ranges::distance(__r), __n)); > else > - return views::repeat(*__r._M_value, __n); > + return views::repeat(*std::forward<_Range>(__r)._M_value, __n); > } > > template > @@ -7813,7 +7822,8 @@ namespace views::__adaptor > if constexpr (sized_range<_Tp>) > { > auto __sz = ranges::distance(__r); > - return views::repeat(*__r._M_value, __sz - std::min(__sz, __n)); > + return views::repeat(*std::forward<_Range>(__r)._M_value, > + __sz - std::min(__sz, __n)); > } > else > return __r; > diff --git a/libstdc++-v3/testsuite/std/ranges/repeat/1.cc b/libstdc++-v3/testsuite/std/ranges/repeat/1.cc > index 30636407ee2..9551414e2c8 100644 > --- a/libstdc++-v3/testsuite/std/ranges/repeat/1.cc > +++ b/libstdc++-v3/testsuite/std/ranges/repeat/1.cc > @@ -2,6 +2,7 @@ > > #include > #include > +#include > #include > > #if __cpp_lib_ranges_repeat != 202207L > @@ -137,6 +138,17 @@ test06() > static_assert( requires { views::repeat(move_only{}, 2); } ); > } > > +void > +test07() > +{ > + // PR libstdc++/112453 > + auto t = std::views::repeat(std::make_unique(5)) | std::views::take(2); > + auto d = std::views::repeat(std::make_unique(5)) | std::views::drop(2); > + > + auto t2 = std::views::repeat(std::make_unique(5), 4) | std::views::take(2); > + auto d2 = std::views::repeat(std::make_unique(5), 4) | std::views::drop(2); > +} > + > int > main() > { > @@ -146,4 +158,5 @@ main() > static_assert(test04()); > test05(); > test06(); > + test07(); > } > -- > 2.43.0.rc1 >