From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id E627F398E43D; Thu, 3 Jun 2021 14:57:59 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org E627F398E43D MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jonathan Wakely To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r10-9887] libstdc++: Fix return value of std::ranges::advance [PR 100833] X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/releases/gcc-10 X-Git-Oldrev: e01562b302eae3d415b43a4efe7ce52cff3e0063 X-Git-Newrev: 753c8680a46d371e179ff1ade36002486361095e Message-Id: <20210603145759.E627F398E43D@sourceware.org> Date: Thu, 3 Jun 2021 14:57:59 +0000 (GMT) X-BeenThere: libstdc++-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 03 Jun 2021 14:58:00 -0000 https://gcc.gnu.org/g:753c8680a46d371e179ff1ade36002486361095e commit r10-9887-g753c8680a46d371e179ff1ade36002486361095e Author: Jonathan Wakely Date: Tue Jun 1 16:02:45 2021 +0100 libstdc++: Fix return value of std::ranges::advance [PR 100833] The three-argument form of ranges::advance is supposed to return the difference between the second argument and the distance the iterator was advanced. When a non-random-access iterator is not advanced (because it already equals the sentinel) we were returning 0 rather than n - 0. libstdc++-v3/ChangeLog: PR libstdc++/100833 * include/bits/range_access.h (ranges::advance(iter, n, sentinel)): Fix return value for no-op case. * testsuite/24_iterators/range_operations/advance.cc: Test return values of three-argument overload. (cherry picked from commit d8326291695c0f13124c232ddf4fd34e3310e649) Diff: --- libstdc++-v3/include/bits/range_access.h | 2 +- .../24_iterators/range_operations/advance.cc | 48 ++++++++++++++-------- 2 files changed, 33 insertions(+), 17 deletions(-) diff --git a/libstdc++-v3/include/bits/range_access.h b/libstdc++-v3/include/bits/range_access.h index d382d1711f3..bf46f366486 100644 --- a/libstdc++-v3/include/bits/range_access.h +++ b/libstdc++-v3/include/bits/range_access.h @@ -1032,7 +1032,7 @@ namespace ranges } } else if (__it == __bound || __n == 0) - return iter_difference_t<_It>(0); + return __n; else if (__n > 0) { iter_difference_t<_It> __m = 0; diff --git a/libstdc++-v3/testsuite/24_iterators/range_operations/advance.cc b/libstdc++-v3/testsuite/24_iterators/range_operations/advance.cc index 429d48f41de..a6121af8e97 100644 --- a/libstdc++-v3/testsuite/24_iterators/range_operations/advance.cc +++ b/libstdc++-v3/testsuite/24_iterators/range_operations/advance.cc @@ -49,10 +49,12 @@ test01() std::ranges::advance(iter, r.begin()); VERIFY( iter == r.begin() ); - std::ranges::advance(iter, 99, r.end()); + auto diff = std::ranges::advance(iter, 99, r.end()); VERIFY( iter == r.end() ); - std::ranges::advance(iter, -222, r.begin()); + VERIFY( diff == 97 ); + diff = std::ranges::advance(iter, -222, r.begin()); VERIFY( iter == r.begin() ); + VERIFY( diff == -220 ); } void @@ -77,10 +79,12 @@ test02() std::ranges::advance(iter, r.begin()); VERIFY( iter == r.begin() ); - std::ranges::advance(iter, 99, r.end()); + auto diff = std::ranges::advance(iter, 99, r.end()); VERIFY( iter == r.end() ); - std::ranges::advance(iter, -222, r.begin()); + VERIFY( diff == 97 ); + diff = std::ranges::advance(iter, -222, r.begin()); VERIFY( iter == r.begin() ); + VERIFY( diff == -220 ); } void @@ -108,15 +112,19 @@ test03() std::ranges::advance(iter, r.end()); VERIFY( iter == r.end() ); - std::ranges::advance(iter, 99, r.end()); + auto diff = std::ranges::advance(iter, 99, r.end()); VERIFY( iter == r.end() ); - std::ranges::advance(iter, 99, r.end()); + VERIFY( diff == 99 ); // PR libstdc++/100833 + diff = std::ranges::advance(iter, 99, r.end()); VERIFY( iter == r.end() ); + VERIFY( diff == 99 ); iter = r.begin(); - std::ranges::advance(iter, 99, r.end()); + diff = std::ranges::advance(iter, 99, r.end()); VERIFY( iter == r.end() ); - std::ranges::advance(iter, 99, r.end()); + VERIFY( diff == 97 ); + diff = std::ranges::advance(iter, 99, r.end()); VERIFY( iter == r.end() ); + VERIFY( diff == 99 ); } void @@ -145,17 +153,21 @@ test04() std::ranges::advance(iter, r2.end()); VERIFY( iter == r2.end() ); - std::ranges::advance(iter, 99, r2.end()); + auto diff = std::ranges::advance(iter, 99, r2.end()); VERIFY( iter == r2.end() ); - std::ranges::advance(iter, 99, r2.end()); + VERIFY( diff == 99 ); + diff = std::ranges::advance(iter, 99, r2.end()); VERIFY( iter == r2.end() ); + VERIFY( diff == 99 ); test_range r3(a); iter = r3.begin(); - std::ranges::advance(iter, 99, r3.end()); + diff = std::ranges::advance(iter, 99, r3.end()); VERIFY( iter == r3.end() ); - std::ranges::advance(iter, 99, r3.end()); + VERIFY( diff == 97 ); + diff = std::ranges::advance(iter, 99, r3.end()); VERIFY( iter == r3.end() ); + VERIFY( diff == 99 ); } void @@ -180,17 +192,21 @@ test05() std::ranges::advance(iter, r2.end()); VERIFY( iter == r2.end() ); - std::ranges::advance(iter, 99, r2.end()); + auto diff = std::ranges::advance(iter, 99, r2.end()); VERIFY( iter == r2.end() ); - std::ranges::advance(iter, 99, r2.end()); + VERIFY( diff == 99 ); + diff = std::ranges::advance(iter, 99, r2.end()); VERIFY( iter == r2.end() ); + VERIFY( diff == 99 ); test_range r3(a); iter = r3.begin(); - std::ranges::advance(iter, 99, r3.end()); + diff = std::ranges::advance(iter, 99, r3.end()); VERIFY( iter == r3.end() ); - std::ranges::advance(iter, 99, r3.end()); + VERIFY( diff == 97 ); + diff = std::ranges::advance(iter, 99, r3.end()); VERIFY( iter == r3.end() ); + VERIFY( diff == 99 ); } int