| Message ID | 20240410085039.267589-1-jwakely@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/4] libstdc++: Heterogeneous std::pair comparisons [PR113386] | expand |
Pushed to trunk now. On Wed, 10 Apr 2024 at 09:51, Jonathan Wakely <jwakely@redhat.com> wrote: > > Tested x86_64-linux. > > Since this only affects C++20 and later it seems OK for trunk now. > > -- >8 -- > > I'm only treating this as a DR for C++20 for now, because it's less work > and only requires changes to operator== and operator<=>. To do this for > older standards would require changes to the six relational operators > used pre-C++20. > > libstdc++-v3/ChangeLog: > > PR libstdc++/113386 > * include/bits/stl_pair.h (operator==, operator<=>): Support > heterogeneous comparisons, as per LWG 3865. > * testsuite/20_util/pair/comparison_operators/lwg3865.cc: New > test. > --- > libstdc++-v3/include/bits/stl_pair.h | 32 ++++++++++++++----- > .../pair/comparison_operators/lwg3865.cc | 15 +++++++++ > 2 files changed, 39 insertions(+), 8 deletions(-) > create mode 100644 libstdc++-v3/testsuite/20_util/pair/comparison_operators/lwg3865.cc > > diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h > index 4f5c8389fa6..45317417c9c 100644 > --- a/libstdc++-v3/include/bits/stl_pair.h > +++ b/libstdc++-v3/include/bits/stl_pair.h > @@ -1000,23 +1000,39 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > template<typename _T1, typename _T2> pair(_T1, _T2) -> pair<_T1, _T2>; > #endif > > - /// Two pairs of the same type are equal iff their members are equal. > - template<typename _T1, typename _T2> > +#if __cpp_lib_three_way_comparison && __cpp_lib_concepts > + // _GLIBCXX_RESOLVE_LIB_DEFECTS > + // 3865. Sorting a range of pairs > + > + /// Two pairs are equal iff their members are equal. > + template<typename _T1, typename _T2, typename _U1, typename _U2> > inline _GLIBCXX_CONSTEXPR bool > - operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) > + operator==(const pair<_T1, _T2>& __x, const pair<_U1, _U2>& __y) > { return __x.first == __y.first && __x.second == __y.second; } > > -#if __cpp_lib_three_way_comparison && __cpp_lib_concepts > - template<typename _T1, typename _T2> > - constexpr common_comparison_category_t<__detail::__synth3way_t<_T1>, > - __detail::__synth3way_t<_T2>> > - operator<=>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) > + /** Defines a lexicographical order for pairs. > + * > + * For two pairs of comparable types, `P` is ordered before `Q` if > + * `P.first` is less than `Q.first`, or if `P.first` and `Q.first` > + * are equivalent (neither is less than the other) and `P.second` is > + * less than `Q.second`. > + */ > + template<typename _T1, typename _T2, typename _U1, typename _U2> > + constexpr common_comparison_category_t<__detail::__synth3way_t<_T1, _U1>, > + __detail::__synth3way_t<_T2, _U2>> > + operator<=>(const pair<_T1, _T2>& __x, const pair<_U1, _U2>& __y) > { > if (auto __c = __detail::__synth3way(__x.first, __y.first); __c != 0) > return __c; > return __detail::__synth3way(__x.second, __y.second); > } > #else > + /// Two pairs of the same type are equal iff their members are equal. > + template<typename _T1, typename _T2> > + inline _GLIBCXX_CONSTEXPR bool > + operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) > + { return __x.first == __y.first && __x.second == __y.second; } > + > /** Defines a lexicographical order for pairs. > * > * For two pairs of the same type, `P` is ordered before `Q` if > diff --git a/libstdc++-v3/testsuite/20_util/pair/comparison_operators/lwg3865.cc b/libstdc++-v3/testsuite/20_util/pair/comparison_operators/lwg3865.cc > new file mode 100644 > index 00000000000..2bbd54af192 > --- /dev/null > +++ b/libstdc++-v3/testsuite/20_util/pair/comparison_operators/lwg3865.cc > @@ -0,0 +1,15 @@ > +// { dg-do run { target c++20 } } > + > +// LWG 3865. Sorting a range of pairs > + > +#include <utility> > +#include <testsuite_hooks.h> > + > +int main() > +{ > + std::pair<int, int> p(1, 2); > + std::pair<int&, int&> p2(p.first, p.second); > + VERIFY( p == p2 ); > + VERIFY( p <= p2 ); > + VERIFY( p >= p2 ); > +} > -- > 2.44.0 >
diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h index 4f5c8389fa6..45317417c9c 100644 --- a/libstdc++-v3/include/bits/stl_pair.h +++ b/libstdc++-v3/include/bits/stl_pair.h @@ -1000,23 +1000,39 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _T1, typename _T2> pair(_T1, _T2) -> pair<_T1, _T2>; #endif - /// Two pairs of the same type are equal iff their members are equal. - template<typename _T1, typename _T2> +#if __cpp_lib_three_way_comparison && __cpp_lib_concepts + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 3865. Sorting a range of pairs + + /// Two pairs are equal iff their members are equal. + template<typename _T1, typename _T2, typename _U1, typename _U2> inline _GLIBCXX_CONSTEXPR bool - operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) + operator==(const pair<_T1, _T2>& __x, const pair<_U1, _U2>& __y) { return __x.first == __y.first && __x.second == __y.second; } -#if __cpp_lib_three_way_comparison && __cpp_lib_concepts - template<typename _T1, typename _T2> - constexpr common_comparison_category_t<__detail::__synth3way_t<_T1>, - __detail::__synth3way_t<_T2>> - operator<=>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) + /** Defines a lexicographical order for pairs. + * + * For two pairs of comparable types, `P` is ordered before `Q` if + * `P.first` is less than `Q.first`, or if `P.first` and `Q.first` + * are equivalent (neither is less than the other) and `P.second` is + * less than `Q.second`. + */ + template<typename _T1, typename _T2, typename _U1, typename _U2> + constexpr common_comparison_category_t<__detail::__synth3way_t<_T1, _U1>, + __detail::__synth3way_t<_T2, _U2>> + operator<=>(const pair<_T1, _T2>& __x, const pair<_U1, _U2>& __y) { if (auto __c = __detail::__synth3way(__x.first, __y.first); __c != 0) return __c; return __detail::__synth3way(__x.second, __y.second); } #else + /// Two pairs of the same type are equal iff their members are equal. + template<typename _T1, typename _T2> + inline _GLIBCXX_CONSTEXPR bool + operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) + { return __x.first == __y.first && __x.second == __y.second; } + /** Defines a lexicographical order for pairs. * * For two pairs of the same type, `P` is ordered before `Q` if diff --git a/libstdc++-v3/testsuite/20_util/pair/comparison_operators/lwg3865.cc b/libstdc++-v3/testsuite/20_util/pair/comparison_operators/lwg3865.cc new file mode 100644 index 00000000000..2bbd54af192 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/pair/comparison_operators/lwg3865.cc @@ -0,0 +1,15 @@ +// { dg-do run { target c++20 } } + +// LWG 3865. Sorting a range of pairs + +#include <utility> +#include <testsuite_hooks.h> + +int main() +{ + std::pair<int, int> p(1, 2); + std::pair<int&, int&> p2(p.first, p.second); + VERIFY( p == p2 ); + VERIFY( p <= p2 ); + VERIFY( p >= p2 ); +}