| Message ID | a16d4ac2-f12e-d3a7-4593-aa9dd490ee1f@verizon.net |
|---|---|
| State | New |
| Headers | show |
| Series | Test for C++20 p0858 - ConstexprIterator requirements. | expand |
On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++ <libstdc++@gcc.gnu.org> wrote: > > Greetings, > > Iterators for <array> and <string_view> are usabe in a constexpr context > since C++2017. > > This just adds a compile test to make sure and check a box for C++20 > p0858 - ConstexprIterator requirements. Those tests don't use the iterators in a constexpr context. To do that, maybe do those std::copy operations in a constexpr function and then initialize a constexpr variable with the result of a call to that function?
On 5/31/19 6:29 PM, Ville Voutilainen wrote: > On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++ > <libstdc++@gcc.gnu.org> wrote: >> Greetings, >> >> Iterators for <array> and <string_view> are usabe in a constexpr context >> since C++2017. >> >> This just adds a compile test to make sure and check a box for C++20 >> p0858 - ConstexprIterator requirements. > > Those tests don't use the iterators in a constexpr context. To do > that, maybe do those std::copy operations > in a constexpr function and then initialize a constexpr variable with > the result of a call to that function? Thanks Ville, I had completely forgotten to make these test functions constexpr - FIXED. Also, instead of bool variables I put the checks in static_asserts. I return functions of (derefed) iterators. I made it so we could run these at C++17 if we want to with '#if __cplusplus == 201703L' the algorithm usage for C++20 only.?? This wasn't a DR though. Anyway, that should do it. Built and tested clean on x86_64-linux. Ok? Ed 2019-06-03 Edward Smith-Rowland <3dw4rd@verizon.net> Test for C++20 p0858 - ConstexprIterator requirements. * testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: New test. * testsuite/23_containers/array/requirements/constexpr_iter.cc: New test. Index: testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc =================================================================== --- testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,37 @@ +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <string_view> +#include <array> + +constexpr char +test() +{ + constexpr std::string_view hw("Hello, World!"); + static_assert('H' == *hw.begin()); + auto ch = hw[4]; + static_assert('W' == *(hw.cbegin() + 7)); + +#if __cplusplus > 201703L + std::array<int, hw.size()> a2{{0,0,0,0,0,0,0,0,0,0,0,0,0}}; + std::copy(hw.begin(), hw.end(), a2.begin()); +#endif + + return *(hw.cbegin() + 3); +} Index: testsuite/23_containers/array/requirements/constexpr_iter.cc =================================================================== --- testsuite/23_containers/array/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/23_containers/array/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,36 @@ +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <array> + +constexpr int +test() +{ + constexpr std::array<int, 3> a1{{1, 2, 3}}; + static_assert(1 == *a1.begin()); + auto n = a1[0] * a1[1]* a1[2]; + static_assert(1 == *a1.cbegin()); + +#if __cplusplus > 201703L + std::array<int, 3> a2{{0, 0, 0}}; + std::copy(a1.begin(), a1.end(), a2.begin()); +#endif + + return n; +}
On Sat, 1 Jun 2019 at 21:09, Ed Smith-Rowland <3dw4rd@verizon.net> wrote: > > On 5/31/19 6:29 PM, Ville Voutilainen wrote: > > On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++ > > <libstdc++@gcc.gnu.org> wrote: > >> Greetings, > >> > >> Iterators for <array> and <string_view> are usabe in a constexpr context > >> since C++2017. > >> > >> This just adds a compile test to make sure and check a box for C++20 > >> p0858 - ConstexprIterator requirements. > > > > Those tests don't use the iterators in a constexpr context. To do > > that, maybe do those std::copy operations > > in a constexpr function and then initialize a constexpr variable with > > the result of a call to that function? > > Thanks Ville, > > I had completely forgotten to make these test functions constexpr - FIXED. ..but that doesn't enforce a constexpr context. If you add another function that calls these functions and initializes a constexpr variable, then we have the enforcement I seek. Such as void test2() { constexpr char x = test(); }
On 6/1/19 2:42 PM, Ville Voutilainen wrote: > On Sat, 1 Jun 2019 at 21:09, Ed Smith-Rowland <3dw4rd@verizon.net> wrote: >> On 5/31/19 6:29 PM, Ville Voutilainen wrote: >>> On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++ >>> <libstdc++@gcc.gnu.org> wrote: >>>> Greetings, >>>> >>>> Iterators for <array> and <string_view> are usabe in a constexpr context >>>> since C++2017. >>>> >>>> This just adds a compile test to make sure and check a box for C++20 >>>> p0858 - ConstexprIterator requirements. >>> Those tests don't use the iterators in a constexpr context. To do >>> that, maybe do those std::copy operations >>> in a constexpr function and then initialize a constexpr variable with >>> the result of a call to that function? >> Thanks Ville, >> >> I had completely forgotten to make these test functions constexpr - FIXED. > .but that doesn't enforce a constexpr context. If you add another > function that calls these functions > and initializes a constexpr variable, then we have the enforcement I > seek. Such as > > void test2() > { > constexpr char x = test(); > } > Ok, third time's a charm. I was brain dead about the constexpr patch.?? I'm now setting a constexpr variable from test() in a caller. But static_assert is a constexpr context no? Ed 2019-06-03 Edward Smith-Rowland <3dw4rd@verizon.net> Test for C++20 p0858 - ConstexprIterator requirements. * testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: New test. * testsuite/23_containers/array/requirements/constexpr_iter.cc: New test. Index: testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc =================================================================== --- testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,43 @@ +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <string_view> +#include <array> + +constexpr char +test() +{ + constexpr std::string_view hw("Hello, World!"); + static_assert('H' == *hw.begin()); + auto ch = hw[4]; + static_assert('W' == *(hw.cbegin() + 7)); + +#if __cplusplus > 201703L + std::array<int, hw.size()> a2{{0,0,0,0,0,0,0,0,0,0,0,0,0}}; + std::copy(hw.begin(), hw.end(), a2.begin()); +#endif + + return *(hw.cbegin() + 3); +} + +void +run_test() +{ + constexpr char ch = test(); +} Index: testsuite/23_containers/array/requirements/constexpr_iter.cc =================================================================== --- testsuite/23_containers/array/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/23_containers/array/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,42 @@ +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <array> + +constexpr int +test() +{ + constexpr std::array<int, 3> a1{{1, 2, 3}}; + static_assert(1 == *a1.begin()); + auto n = a1[0] * a1[1]* a1[2]; + static_assert(1 == *a1.cbegin()); + +#if __cplusplus > 201703L + std::array<int, 3> a2{{0, 0, 0}}; + std::copy(a1.begin(), a1.end(), a2.begin()); +#endif + + return n; +} + +void +run_test() +{ + constexpr int n = test(); +}
On Sat, 1 Jun 2019 at 22:40, Ed Smith-Rowland <3dw4rd@verizon.net> wrote: > Ok, third time's a charm. > > I was brain dead about the constexpr patch.?? I'm now setting a constexpr > variable from test() in a caller. Looks good. Jonathan needs to approve it, though. > But static_assert is a constexpr context no? Yes, it is. It's just that now all of test() is verified to be okay as a constant expression, including std::copy.
On 01/06/19 15:40 -0400, Ed Smith-Rowland via libstdc++ wrote: >On 6/1/19 2:42 PM, Ville Voutilainen wrote: >>On Sat, 1 Jun 2019 at 21:09, Ed Smith-Rowland <3dw4rd@verizon.net> wrote: >>>On 5/31/19 6:29 PM, Ville Voutilainen wrote: >>>>On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++ >>>><libstdc++@gcc.gnu.org> wrote: >>>>>Greetings, >>>>> >>>>>Iterators for <array> and <string_view> are usabe in a constexpr context >>>>>since C++2017. >>>>> >>>>>This just adds a compile test to make sure and check a box for C++20 >>>>>p0858 - ConstexprIterator requirements. >>>>Those tests don't use the iterators in a constexpr context. To do >>>>that, maybe do those std::copy operations >>>>in a constexpr function and then initialize a constexpr variable with >>>>the result of a call to that function? >>>Thanks Ville, >>> >>>I had completely forgotten to make these test functions constexpr - FIXED. >>.but that doesn't enforce a constexpr context. If you add another >>function that calls these functions >>and initializes a constexpr variable, then we have the enforcement I >>seek. Such as >> >>void test2() >>{ >> constexpr char x = test(); >>} >> >Ok, third time's a charm. > >I was brain dead about the constexpr patch.?? I'm now setting a >constexpr variable from test() in a caller. > >But static_assert is a constexpr context no? > >Ed > > >2019-06-03 Edward Smith-Rowland <3dw4rd@verizon.net> > > Test for C++20 p0858 - ConstexprIterator requirements. > * testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: > New test. > * testsuite/23_containers/array/requirements/constexpr_iter.cc: > New test. > >Index: testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >=================================================================== >--- testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (nonexistent) >+++ testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (working copy) >@@ -0,0 +1,43 @@ >+// { dg-do compile { target c++2a } } Please check the testsuite/libstdc++.log or testsuite/libstdc++.sum files for the new tests. I expect they are both UNSUPPORTED. That's because you've given a target c++2a which means they won't be run unless a suitable -std option is given. And you haven't given one. You need to add { dg-options "-std=gnu++2a" } before the dg-do line. Also if the tests are restricted to C++2a then there's no point having the #if __cplusplus > 201703L check, because that will never be false.
On 07/06/19 16:42 +0100, Jonathan Wakely wrote: >On 01/06/19 15:40 -0400, Ed Smith-Rowland via libstdc++ wrote: >>On 6/1/19 2:42 PM, Ville Voutilainen wrote: >>>On Sat, 1 Jun 2019 at 21:09, Ed Smith-Rowland <3dw4rd@verizon.net> wrote: >>>>On 5/31/19 6:29 PM, Ville Voutilainen wrote: >>>>>On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++ >>>>><libstdc++@gcc.gnu.org> wrote: >>>>>>Greetings, >>>>>> >>>>>>Iterators for <array> and <string_view> are usabe in a constexpr context >>>>>>since C++2017. >>>>>> >>>>>>This just adds a compile test to make sure and check a box for C++20 >>>>>>p0858 - ConstexprIterator requirements. >>>>>Those tests don't use the iterators in a constexpr context. To do >>>>>that, maybe do those std::copy operations >>>>>in a constexpr function and then initialize a constexpr variable with >>>>>the result of a call to that function? >>>>Thanks Ville, >>>> >>>>I had completely forgotten to make these test functions constexpr - FIXED. >>>.but that doesn't enforce a constexpr context. If you add another >>>function that calls these functions >>>and initializes a constexpr variable, then we have the enforcement I >>>seek. Such as >>> >>>void test2() >>>{ >>> constexpr char x = test(); >>>} >>> >>Ok, third time's a charm. >> >>I was brain dead about the constexpr patch.?? I'm now setting a >>constexpr variable from test() in a caller. >> >>But static_assert is a constexpr context no? >> >>Ed >> >> > >>2019-06-03 Edward Smith-Rowland <3dw4rd@verizon.net> >> >> Test for C++20 p0858 - ConstexprIterator requirements. >> * testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: >> New test. >> * testsuite/23_containers/array/requirements/constexpr_iter.cc: >> New test. >> > >>Index: testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >>=================================================================== >>--- testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (nonexistent) >>+++ testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (working copy) >>@@ -0,0 +1,43 @@ >>+// { dg-do compile { target c++2a } } > >Please check the testsuite/libstdc++.log or testsuite/libstdc++.sum >files for the new tests. I expect they are both UNSUPPORTED. > >That's because you've given a target c++2a which means they won't be >run unless a suitable -std option is given. And you haven't given one. > >You need to add { dg-options "-std=gnu++2a" } before the dg-do line. > >Also if the tests are restricted to C++2a then there's no point having >the #if __cplusplus > 201703L check, because that will never be false. I've enhanced my badtests.awk script to check for this case, and it found a problem with 24_iterators/container_access.cc (the dg-options needs to be first or the -std option isn't used when checking the effective target). Tested x86_64-linux, committed to trunk.
On 6/7/19 11:42 AM, Jonathan Wakely wrote: > On 01/06/19 15:40 -0400, Ed Smith-Rowland via libstdc++ wrote: >> On 6/1/19 2:42 PM, Ville Voutilainen wrote: >>> On Sat, 1 Jun 2019 at 21:09, Ed Smith-Rowland <3dw4rd@verizon.net> >>> wrote: >>>> On 5/31/19 6:29 PM, Ville Voutilainen wrote: >>>>> On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++ >>>>> <libstdc++@gcc.gnu.org> wrote: >>>>>> Greetings, >>>>>> >>>>>> Iterators for <array> and <string_view> are usabe in a constexpr >>>>>> context >>>>>> since C++2017. >>>>>> >>>>>> This just adds a compile test to make sure and check a box for C++20 >>>>>> p0858 - ConstexprIterator requirements. >>>>> Those tests don't use the iterators in a constexpr context. To do >>>>> that, maybe do those std::copy operations >>>>> in a constexpr function and then initialize a constexpr variable with >>>>> the result of a call to that function? >>>> Thanks Ville, >>>> >>>> I had completely forgotten to make these test functions constexpr - >>>> FIXED. >>> .but that doesn't enforce a constexpr context. If you add another >>> function that calls these functions >>> and initializes a constexpr variable, then we have the enforcement I >>> seek. Such as >>> >>> void test2() >>> { >>> ?????? constexpr char x = test(); >>> } >>> >> Ok, third time's a charm. >> >> I was brain dead about the constexpr patch.?? I'm now setting a >> constexpr variable from test() in a caller. >> >> But static_assert is a constexpr context no? >> >> Ed >> >> > >> 2019-06-03?? Edward Smith-Rowland <3dw4rd@verizon.net> >> >> ????????Test for C++20 p0858 - ConstexprIterator requirements. >> ????????* >> testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: >> ????????New test. >> ????????* testsuite/23_containers/array/requirements/constexpr_iter.cc: >> ????????New test. >> > >> Index: >> testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >> =================================================================== >> --- >> testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >> (nonexistent) >> +++ >> testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >> (working copy) >> @@ -0,0 +1,43 @@ >> +// { dg-do compile { target c++2a } } > > Please check the testsuite/libstdc++.log or testsuite/libstdc++.sum > files for the new tests. I expect they are both UNSUPPORTED. > > That's because you've given a target c++2a which means they won't be > run unless a suitable -std option is given. And you haven't given one. > > You need to add { dg-options "-std=gnu++2a" } before the dg-do line. > > Also if the tests are restricted to C++2a then there's no point having > the #if __cplusplus > 201703L check, because that will never be false. > I had supplied the option for gnu++2a by hand and they passed.?? They were not UNSUPPORTED. I just added the dg-options (at very top) and reran the testsuite without fancy tricks (except for gnu++2a). I also took out the #if __cplusplus.?? I was just playing around and discovered that these pass in C++17 if you comment out the C++20 constexpr algos. OK for trunk? Also, we could declare victory for this for gcc-9.?? May I backport after this is in? Ed 2019-06-10 Edward Smith-Rowland <3dw4rd@verizon.net> Test for C++20 p0858 - ConstexprIterator requirements. * testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: New test. * testsuite/23_containers/array/requirements/constexpr_iter.cc: New test. Index: testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc =================================================================== --- testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,42 @@ +// { dg-options "-std=gnu++2a" } +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <string_view> +#include <array> + +constexpr char +test() +{ + constexpr std::string_view hw("Hello, World!"); + static_assert('H' == *hw.begin()); + auto ch = hw[4]; + static_assert('W' == *(hw.cbegin() + 7)); + + std::array<int, hw.size()> a2{{0,0,0,0,0,0,0,0,0,0,0,0,0}}; + std::copy(hw.begin(), hw.end(), a2.begin()); + + return *(hw.cbegin() + 3); +} + +void +run_test() +{ + constexpr char ch = test(); +} Index: testsuite/23_containers/array/requirements/constexpr_iter.cc =================================================================== --- testsuite/23_containers/array/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/23_containers/array/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,41 @@ +// { dg-options "-std=gnu++2a" } +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <array> + +constexpr int +test() +{ + constexpr std::array<int, 3> a1{{1, 2, 3}}; + static_assert(1 == *a1.begin()); + auto n = a1[0] * a1[1]* a1[2]; + static_assert(1 == *a1.cbegin()); + + std::array<int, 3> a2{{0, 0, 0}}; + std::copy(a1.begin(), a1.end(), a2.begin()); + + return n; +} + +void +run_test() +{ + constexpr int n = test(); +}
On 08/06/19 12:05 -0400, Ed Smith-Rowland wrote: >On 6/7/19 11:42 AM, Jonathan Wakely wrote: >>On 01/06/19 15:40 -0400, Ed Smith-Rowland via libstdc++ wrote: >>>On 6/1/19 2:42 PM, Ville Voutilainen wrote: >>>>On Sat, 1 Jun 2019 at 21:09, Ed Smith-Rowland >>>><3dw4rd@verizon.net> wrote: >>>>>On 5/31/19 6:29 PM, Ville Voutilainen wrote: >>>>>>On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++ >>>>>><libstdc++@gcc.gnu.org> wrote: >>>>>>>Greetings, >>>>>>> >>>>>>>Iterators for <array> and <string_view> are usabe in a >>>>>>>constexpr context >>>>>>>since C++2017. >>>>>>> >>>>>>>This just adds a compile test to make sure and check a box for C++20 >>>>>>>p0858 - ConstexprIterator requirements. >>>>>>Those tests don't use the iterators in a constexpr context. To do >>>>>>that, maybe do those std::copy operations >>>>>>in a constexpr function and then initialize a constexpr variable with >>>>>>the result of a call to that function? >>>>>Thanks Ville, >>>>> >>>>>I had completely forgotten to make these test functions >>>>>constexpr - FIXED. >>>>.but that doesn't enforce a constexpr context. If you add another >>>>function that calls these functions >>>>and initializes a constexpr variable, then we have the enforcement I >>>>seek. Such as >>>> >>>>void test2() >>>>{ >>>>?????? constexpr char x = test(); >>>>} >>>> >>>Ok, third time's a charm. >>> >>>I was brain dead about the constexpr patch.?? I'm now setting a >>>constexpr variable from test() in a caller. >>> >>>But static_assert is a constexpr context no? >>> >>>Ed >>> >>> >> >>>2019-06-03?? Edward Smith-Rowland <3dw4rd@verizon.net> >>> >>>????????Test for C++20 p0858 - ConstexprIterator requirements. >>>????????* testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: >>>????????New test. >>>????????* testsuite/23_containers/array/requirements/constexpr_iter.cc: >>>????????New test. >>> >> >>>Index: testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >>>=================================================================== >>>--- testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >>>(nonexistent) >>>+++ testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >>>(working copy) >>>@@ -0,0 +1,43 @@ >>>+// { dg-do compile { target c++2a } } >> >>Please check the testsuite/libstdc++.log or testsuite/libstdc++.sum >>files for the new tests. I expect they are both UNSUPPORTED. >> >>That's because you've given a target c++2a which means they won't be >>run unless a suitable -std option is given. And you haven't given one. >> >>You need to add { dg-options "-std=gnu++2a" } before the dg-do line. >> >>Also if the tests are restricted to C++2a then there's no point having >>the #if __cplusplus > 201703L check, because that will never be false. >> >I had supplied the option for gnu++2a by hand and they passed.?? They >were not UNSUPPORTED. > >I just added the dg-options (at very top) and reran the testsuite >without fancy tricks (except for gnu++2a). > >I also took out the #if __cplusplus.?? I was just playing around and >discovered that these pass in C++17 if you comment out the C++20 >constexpr algos. > >OK for trunk? OK for trunk. >Also, we could declare victory for this for gcc-9.?? May I backport >after this is in? Yes, these tests are also OK to backport to gcc-9-branch (assuming they pass on the branch, which I agree they should do). Thanks!
On 6/8/19 4:28 PM, Jonathan Wakely wrote: > On 08/06/19 12:05 -0400, Ed Smith-Rowland wrote: >> On 6/7/19 11:42 AM, Jonathan Wakely wrote: >>> On 01/06/19 15:40 -0400, Ed Smith-Rowland via libstdc++ wrote: >>>> On 6/1/19 2:42 PM, Ville Voutilainen wrote: >>>>> On Sat, 1 Jun 2019 at 21:09, Ed Smith-Rowland <3dw4rd@verizon.net> >>>>> wrote: >>>>>> On 5/31/19 6:29 PM, Ville Voutilainen wrote: >>>>>>> On Sat, 1 Jun 2019 at 01:24, Ed Smith-Rowland via libstdc++ >>>>>>> <libstdc++@gcc.gnu.org> wrote: >>>>>>>> Greetings, >>>>>>>> >>>>>>>> Iterators for <array> and <string_view> are usabe in a >>>>>>>> constexpr context >>>>>>>> since C++2017. >>>>>>>> >>>>>>>> This just adds a compile test to make sure and check a box for >>>>>>>> C++20 >>>>>>>> p0858 - ConstexprIterator requirements. >>>>>>> Those tests don't use the iterators in a constexpr context. To do >>>>>>> that, maybe do those std::copy operations >>>>>>> in a constexpr function and then initialize a constexpr variable >>>>>>> with >>>>>>> the result of a call to that function? >>>>>> Thanks Ville, >>>>>> >>>>>> I had completely forgotten to make these test functions constexpr >>>>>> - FIXED. >>>>> .but that doesn't enforce a constexpr context. If you add another >>>>> function that calls these functions >>>>> and initializes a constexpr variable, then we have the enforcement I >>>>> seek. Such as >>>>> >>>>> void test2() >>>>> { >>>>> ?????? constexpr char x = test(); >>>>> } >>>>> >>>> Ok, third time's a charm. >>>> >>>> I was brain dead about the constexpr patch.?? I'm now setting a >>>> constexpr variable from test() in a caller. >>>> >>>> But static_assert is a constexpr context no? >>>> >>>> Ed >>>> >>>> >>> >>>> 2019-06-03?? Edward Smith-Rowland <3dw4rd@verizon.net> >>>> >>>> ????????Test for C++20 p0858 - ConstexprIterator requirements. >>>> ????????* >>>> testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: >>>> ????????New test. >>>> ????????* >>>> testsuite/23_containers/array/requirements/constexpr_iter.cc: >>>> ????????New test. >>>> >>> >>>> Index: >>>> testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >>>> =================================================================== >>>> --- >>>> testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >>>> (nonexistent) >>>> +++ >>>> testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc >>>> (working copy) >>>> @@ -0,0 +1,43 @@ >>>> +// { dg-do compile { target c++2a } } >>> >>> Please check the testsuite/libstdc++.log or testsuite/libstdc++.sum >>> files for the new tests. I expect they are both UNSUPPORTED. >>> >>> That's because you've given a target c++2a which means they won't be >>> run unless a suitable -std option is given. And you haven't given one. >>> >>> You need to add { dg-options "-std=gnu++2a" } before the dg-do line. >>> >>> Also if the tests are restricted to C++2a then there's no point having >>> the #if __cplusplus > 201703L check, because that will never be false. >>> >> I had supplied the option for gnu++2a by hand and they passed.?? They >> were not UNSUPPORTED. >> >> I just added the dg-options (at very top) and reran the testsuite >> without fancy tricks (except for gnu++2a). >> >> I also took out the #if __cplusplus.?? I was just playing around and >> discovered that these pass in C++17 if you comment out the C++20 >> constexpr algos. >> >> OK for trunk? > > OK for trunk. Committed 272084. > >> Also, we could declare victory for this for gcc-9.?? May I backport >> after this is in? > > Yes, these tests are also OK to backport to gcc-9-branch (assuming > they pass on the branch, which I agree they should do). > > Thanks! > The backport is the same less the calls to std::copy. CL and patch attached. Committed 272097. Ed 2019-06-09 Edward Smith-Rowland <3dw4rd@verizon.net> Test for C++20 p0858 - ConstexprIterator requirements. * testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: New test. * testsuite/23_containers/array/requirements/constexpr_iter.cc: New test. Index: testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc =================================================================== --- testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,39 @@ +// { dg-options "-std=gnu++2a" } +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <string_view> +#include <array> + +constexpr char +test() +{ + constexpr std::string_view hw("Hello, World!"); + static_assert('H' == *hw.begin()); + auto ch = hw[4]; + static_assert('W' == *(hw.cbegin() + 7)); + + return *(hw.cbegin() + 3); +} + +void +run_test() +{ + constexpr char ch = test(); +} Index: testsuite/23_containers/array/requirements/constexpr_iter.cc =================================================================== --- testsuite/23_containers/array/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/23_containers/array/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,38 @@ +// { dg-options "-std=gnu++2a" } +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <array> + +constexpr int +test() +{ + constexpr std::array<int, 3> a1{{1, 2, 3}}; + static_assert(1 == *a1.begin()); + auto n = a1[0] * a1[1]* a1[2]; + static_assert(1 == *a1.cbegin()); + + return n; +} + +void +run_test() +{ + constexpr int n = test(); +}
Hi Ed, >>> I had supplied the option for gnu++2a by hand and they passed.?? They >>> were not UNSUPPORTED. >>> >>> I just added the dg-options (at very top) and reran the testsuite >>> without fancy tricks (except for gnu++2a). >>> >>> I also took out the #if __cplusplus.?? I was just playing around and >>> discovered that these pass in C++17 if you comment out the C++20 >>> constexpr algos. >>> >>> OK for trunk? >> >> OK for trunk. > Committed 272084. 272085 actually ;-) Unfortunately, the new tests seem to FAIL (almost?) everywhere: +FAIL: 21_strings/basic_string_view/requirements/constexpr_iter.cc (test for excess errors) Excess errors: /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:33: error: call to non-'constexpr' function '_OI std::copy(_II, _II, _OI) [with _II = const char*; _OI = int*]' /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:41: error: 'constexpr char test()' called in a constant expression +FAIL: 23_containers/array/requirements/constexpr_iter.cc (test for excess errors) /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc:32: error: call to non-'constexpr' function '_OI std::copy(_II, _II, _OI) [with _II = const int*; _OI = int*]' /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc:40: error: 'constexpr int test()' called in a constant expression I'm seeing those on i386-pc-solaris2.11 and sparc-sun-solaris2.11, and there are gcc-testresults reports on aarch64-unknown-linux-gnu, i686-pc-linux-gnu, powerpc64le-unknown-linux-gnu, and x86_64-pc-linux-gnu, among others. Please fix. Rainer
On Mon, 10 Jun 2019 at 01:03, Rainer Orth <ro@cebitec.uni-bielefeld.de> wrote: > > Hi Ed, > > >>> I had supplied the option for gnu++2a by hand and they passed.?? They > >>> were not UNSUPPORTED. > >>> > >>> I just added the dg-options (at very top) and reran the testsuite > >>> without fancy tricks (except for gnu++2a). > >>> > >>> I also took out the #if __cplusplus.?? I was just playing around and > >>> discovered that these pass in C++17 if you comment out the C++20 > >>> constexpr algos. > >>> > >>> OK for trunk? > >> > >> OK for trunk. > > Committed 272084. > > 272085 actually ;-) Unfortunately, the new tests seem to FAIL (almost?) > everywhere: > > +FAIL: 21_strings/basic_string_view/requirements/constexpr_iter.cc (test for excess errors) > > Excess errors: > /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:33: error: call to non-'constexpr' function '_OI std::copy(_II, _II, _OI) [with _II = const char*; _OI = int*]' > /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:41: error: 'constexpr char test()' called in a constant expression > > +FAIL: 23_containers/array/requirements/constexpr_iter.cc (test for excess errors) > > /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc:32: error: call to non-'constexpr' function '_OI std::copy(_II, _II, _OI) [with _II = const int*; _OI = int*]' > /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc:40: error: 'constexpr int test()' called in a constant expression > > I'm seeing those on i386-pc-solaris2.11 and sparc-sun-solaris2.11, and > there are gcc-testresults reports on aarch64-unknown-linux-gnu, > i686-pc-linux-gnu, powerpc64le-unknown-linux-gnu, and > x86_64-pc-linux-gnu, among others. > > Please fix. Indeed. std::copy isn't constexpr yet. I don't see how Ed's test run can pass. We either need to put this on hold until enough of <algorithm> is constexprified, or we need to use loops in this test and test (constexpr) algorithms' use of (constexpr) iterators separately later.
On 10/06/19 00:03 +0200, Rainer Orth wrote: >Hi Ed, > >>>> I had supplied the option for gnu++2a by hand and they passed.?? They >>>> were not UNSUPPORTED. >>>> >>>> I just added the dg-options (at very top) and reran the testsuite >>>> without fancy tricks (except for gnu++2a). >>>> >>>> I also took out the #if __cplusplus.?? I was just playing around and >>>> discovered that these pass in C++17 if you comment out the C++20 >>>> constexpr algos. >>>> >>>> OK for trunk? >>> >>> OK for trunk. >> Committed 272084. > >272085 actually ;-) Unfortunately, the new tests seem to FAIL (almost?) >everywhere: > >+FAIL: 21_strings/basic_string_view/requirements/constexpr_iter.cc (test for excess errors) > >Excess errors: >/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:33: error: call to non-'constexpr' function '_OI std::copy(_II, _II, _OI) [with _II = const char*; _OI = int*]' >/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:41: error: 'constexpr char test()' called in a constant expression > >+FAIL: 23_containers/array/requirements/constexpr_iter.cc (test for excess errors) > >/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc:32: error: call to non-'constexpr' function '_OI std::copy(_II, _II, _OI) [with _II = const int*; _OI = int*]' >/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc:40: error: 'constexpr int test()' called in a constant expression > >I'm seeing those on i386-pc-solaris2.11 and sparc-sun-solaris2.11, and >there are gcc-testresults reports on aarch64-unknown-linux-gnu, >i686-pc-linux-gnu, powerpc64le-unknown-linux-gnu, and >x86_64-pc-linux-gnu, among others. Presumably because std::copy isn't actually constexpr yet. Ed, do you have uncommitted local changes that allow this test to pass? Because I don't see how it can pass otherwise.
On 6/9/19 6:28 PM, Jonathan Wakely wrote: > On 10/06/19 00:03 +0200, Rainer Orth wrote: >> Hi Ed, >> >>>>> I had supplied the option for gnu++2a by hand and they passed.?? They >>>>> were not UNSUPPORTED. >>>>> >>>>> I just added the dg-options (at very top) and reran the testsuite >>>>> without fancy tricks (except for gnu++2a). >>>>> >>>>> I also took out the #if __cplusplus.?? I was just playing around and >>>>> discovered that these pass in C++17 if you comment out the C++20 >>>>> constexpr algos. >>>>> >>>>> OK for trunk? >>>> >>>> OK for trunk. >>> Committed 272084. >> >> 272085 actually ;-)?? Unfortunately, the new tests seem to FAIL (almost?) >> everywhere: >> >> +FAIL: 21_strings/basic_string_view/requirements/constexpr_iter.cc >> (test for excess errors) >> >> Excess errors: >> /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:33: >> error: call to non-'constexpr' function '_OI std::copy(_II, _II, _OI) >> [with _II = const char*; _OI = int*]' >> /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc:41: >> error: 'constexpr char test()' called in a constant expression >> >> +FAIL: 23_containers/array/requirements/constexpr_iter.cc (test for >> excess errors) >> >> /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc:32: >> error: call to non-'constexpr' function '_OI std::copy(_II, _II, _OI) >> [with _II = const int*; _OI = int*]' >> /vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc:40: >> error: 'constexpr int test()' called in a constant expression >> >> I'm seeing those on i386-pc-solaris2.11 and sparc-sun-solaris2.11, and >> there are gcc-testresults reports on aarch64-unknown-linux-gnu, >> i686-pc-linux-gnu, powerpc64le-unknown-linux-gnu, and >> x86_64-pc-linux-gnu, among others. > > Presumably because std::copy isn't actually constexpr yet. > > Ed, do you have uncommitted local changes that allow this test to > pass? Because I don't see how it can pass otherwise. > Darn it, I had those constexpr lib patches in tree. Attached are what I just committed to gcc-9 and passes there. Those std::copy didn't really add anything anyway. Note to self - no matter how small work on a separate branch. I'm testing on a new clean branch unless someone beats me to it. Sorry for all the noise. Ed Index: testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc =================================================================== --- testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (revision 272098) +++ testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (working copy) @@ -29,9 +29,6 @@ auto ch = hw[4]; static_assert('W' == *(hw.cbegin() + 7)); - std::array<int, hw.size()> a2{{0,0,0,0,0,0,0,0,0,0,0,0,0}}; - std::copy(hw.begin(), hw.end(), a2.begin()); - return *(hw.cbegin() + 3); } Index: testsuite/23_containers/array/requirements/constexpr_iter.cc =================================================================== --- testsuite/23_containers/array/requirements/constexpr_iter.cc (revision 272098) +++ testsuite/23_containers/array/requirements/constexpr_iter.cc (working copy) @@ -28,9 +28,6 @@ auto n = a1[0] * a1[1]* a1[2]; static_assert(1 == *a1.cbegin()); - std::array<int, 3> a2{{0, 0, 0}}; - std::copy(a1.begin(), a1.end(), a2.begin()); - return n; }
On Mon, 10 Jun 2019 at 02:53, Ed Smith-Rowland <3dw4rd@verizon.net> wrote: > Darn it, I had those constexpr lib patches in tree. > Attached are what I just committed to gcc-9 and passes there. Those > std::copy didn't really add anything anyway. They added a test that *i++ = *j++ works, and that i != j works.
On 6/10/19 2:43 AM, Ville Voutilainen wrote: > On Mon, 10 Jun 2019 at 02:53, Ed Smith-Rowland <3dw4rd@verizon.net> wrote: > >> Darn it, I had those constexpr lib patches in tree. >> Attached are what I just committed to gcc-9 and passes there. Those >> std::copy didn't really add anything anyway. > They added a test that *i++ = *j++ works, and that i != j works. > Ok, Here is a version that adds back a hand written copy thing to test Ville's observation. This is tested on a clean branch. I would also like to add the same copy lines to the gcc-9 branch. OK? Ed 2019-06-11 Edward Smith-Rowland <3dw4rd@verizon.net> Test C++20 - p0858 ConstexprIterator requirements. * testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc: New test. * testsuite/23_containers/array/requirements/constexpr_iter.cc: New test. diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc index 24ab502372a..799fb0391f5 100644 --- a/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc +++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc @@ -30,7 +30,11 @@ test() static_assert('W' == *(hw.cbegin() + 7)); std::array<int, hw.size()> a2{{0,0,0,0,0,0,0,0,0,0,0,0,0}}; - std::copy(hw.begin(), hw.end(), a2.begin()); + auto hwi = hw.begin(); + auto hwe = hw.end(); + auto a2i = a2.begin(); + while (hwi != hwe) + *a2i++ = *hwi++; return *(hw.cbegin() + 3); } diff --git a/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc b/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc index 88d69d2f8c7..4b5346631c9 100644 --- a/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc +++ b/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc @@ -27,9 +27,13 @@ test() static_assert(1 == *a1.begin()); auto n = a1[0] * a1[1]* a1[2]; static_assert(1 == *a1.cbegin()); - + std::array<int, 3> a2{{0, 0, 0}}; - std::copy(a1.begin(), a1.end(), a2.begin()); + auto a1i = a1.begin(); + auto a1e = a1.end(); + auto a2i = a2.begin(); + while (a1i != a1e) + *a2i++ = *a1i++; return n; }
On 10/06/19 18:46 -0400, Ed Smith-Rowland via libstdc++ wrote: >On 6/10/19 2:43 AM, Ville Voutilainen wrote: >>On Mon, 10 Jun 2019 at 02:53, Ed Smith-Rowland <3dw4rd@verizon.net> wrote: >> >>>Darn it, I had those constexpr lib patches in tree. >>>Attached are what I just committed to gcc-9 and passes there. Those >>>std::copy didn't really add anything anyway. >>They added a test that *i++ = *j++ works, and that i != j works. >> >Ok, > >Here is a version that adds back a hand written copy thing to test >Ville's observation. > >This is tested on a clean branch. > >I would also like to add the same copy lines to the gcc-9 branch. > >OK? Ok for trunk and gcc-9-branch, thanks.
Index: testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc =================================================================== --- testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/21_strings/basic_string_view/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,33 @@ +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <string_view> +#include <array> + +void +test() +{ + constexpr std::string_view hw("Hello, World!"); + bool ok = 'H' == *hw.begin(); + auto ch = hw[4]; + bool cok = 'W' == *(hw.cbegin() + 7); + + std::array<int, hw.size()> a2{{0,0,0,0,0,0,0,0,0,0,0,0,0}}; + std::copy(hw.begin(), hw.end(), a2.begin()); +} Index: testsuite/23_containers/array/requirements/constexpr_iter.cc =================================================================== --- testsuite/23_containers/array/requirements/constexpr_iter.cc (nonexistent) +++ testsuite/23_containers/array/requirements/constexpr_iter.cc (working copy) @@ -0,0 +1,32 @@ +// { dg-do compile { target c++2a } } +// +// Copyright (C) 2019 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +#include <array> + +void +test() +{ + constexpr std::array<int, 3> a1{{1, 2, 3}}; + bool ok = 1 == *a1.begin(); + auto n = a1[0] * a1[1]* a1[2]; + bool cok = 1 == *a1.cbegin(); + + std::array<int, 3> a2{{0, 0, 0}}; + std::copy(a1.begin(), a1.end(), a2.begin()); +}