diff options
| author | Jonathan Wakely <jwakely@redhat.com> | 2020-01-29 13:56:49 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2020-01-29 13:56:49 +0000 |
| commit | f214ffb336d582a66149068a2a96b7fcf395b5de (patch) | |
| tree | 1cf499bba1c63de4edf244c2387cb30777eceaf8 /libstdc++-v3/libsupc++ | |
| parent | 83b0201035cfdc1d4d80153f4e19ec98cf059941 (diff) | |
libstdc++: Simplify constraints on std::compare_three_way
The __3way_builtin_ptr_cmp concept can use three_way_comparable_with to
check whether <=> is valid. Doing that makes it obvious that the
disjunction on compare_three_way::operator() is redundant, because
the second constraint subsumes the first.
The workaround for PR c++/91073 can also be removed as that bug is fixed
now.
* libsupc++/compare (__detail::__3way_builtin_ptr_cmp): Use
three_way_comparable_with.
(__detail::__3way_cmp_with): Remove workaround for fixed bug.
(compare_three_way::operator()): Remove redundant constraint from
requires-clause.
(__detail::_Synth3way::operator()): Use three_way_comparable_with
instead of workaround.
* testsuite/18_support/comparisons/object/93479.cc: Prune extra
output due to simplified constraints on compare_three_way::operator().
Diffstat (limited to 'libstdc++-v3/libsupc++')
| -rw-r--r-- | libstdc++-v3/libsupc++/compare | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/libstdc++-v3/libsupc++/compare b/libstdc++-v3/libsupc++/compare index aabd0c56530..a7a29ef0440 100644 --- a/libstdc++-v3/libsupc++/compare +++ b/libstdc++-v3/libsupc++/compare @@ -525,26 +525,20 @@ namespace std // BUILTIN-PTR-THREE-WAY(T, U) template<typename _Tp, typename _Up> concept __3way_builtin_ptr_cmp - = requires(_Tp&& __t, _Up&& __u) - { static_cast<_Tp&&>(__t) <=> static_cast<_Up&&>(__u); } + = three_way_comparable_with<_Tp, _Up> && convertible_to<_Tp, const volatile void*> && convertible_to<_Up, const volatile void*> && ! requires(_Tp&& __t, _Up&& __u) { operator<=>(static_cast<_Tp&&>(__t), static_cast<_Up&&>(__u)); } && ! requires(_Tp&& __t, _Up&& __u) { static_cast<_Tp&&>(__t).operator<=>(static_cast<_Up&&>(__u)); }; - - // FIXME: workaround for PR c++/91073 - template<typename _Tp, typename _Up> - concept __3way_cmp_with = three_way_comparable_with<_Tp, _Up>; } // namespace __detail // [cmp.object], typename compare_three_way struct compare_three_way { template<typename _Tp, typename _Up> - requires (__detail::__3way_cmp_with<_Tp, _Up> - || __detail::__3way_builtin_ptr_cmp<_Tp, _Up>) + requires three_way_comparable_with<_Tp, _Up> constexpr auto operator()(_Tp&& __t, _Up&& __u) const noexcept { @@ -919,7 +913,7 @@ namespace std { __u < __t } -> convertible_to<bool>; } { - if constexpr (__3way_cmp_with<_Tp, _Up>) + if constexpr (three_way_comparable_with<_Tp, _Up>) return __t <=> __u; else { |