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| author | Jonathan Wakely <jwakely@redhat.com> | 2019-12-05 00:42:06 +0000 |
|---|---|---|
| committer | Jonathan Wakely <redi@gcc.gnu.org> | 2019-12-05 00:42:06 +0000 |
| commit | 3a4cc6281b56c52136cc755e46776c025114d865 (patch) | |
| tree | 204b53d72bcd8d72a429ccc276d959002b69f048 /libstdc++-v3/include/std/array | |
| parent | 880c7b8c2570544ae4218374688a10a98c9d6542 (diff) | |
| download | gcc-3a4cc6281b56c52136cc755e46776c025114d865.zip gcc-3a4cc6281b56c52136cc755e46776c025114d865.tar.gz gcc-3a4cc6281b56c52136cc755e46776c025114d865.tar.bz2 | |
libstdc++: Implement spaceship for std::array (P1614R2)
As done for std::pair, this defines operator<=> as a non-member function
template and does not alter operator==, as expected to be proposed as
the resolution to an unpublished LWG issue.
Instead of calling std::lexicographical_compare_three_way the <=>
overload is implemented by hand to take advantage of the fact the
element types and array sizes are known to be the same.
* include/bits/cpp_type_traits.h (__is_byte<char8_t>): Add
specialization.
* include/std/array (operator<=>): Likewise.
* testsuite/23_containers/array/comparison_operators/constexpr.cc:
Test three-way comparisons and arrays of unsigned char.
* testsuite/23_containers/array/tuple_interface/get_neg.cc: Adjust
dg-error line numbers.
From-SVN: r278981
Diffstat (limited to 'libstdc++-v3/include/std/array')
| -rw-r--r-- | libstdc++-v3/include/std/array | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/libstdc++-v3/include/std/array b/libstdc++-v3/include/std/array index 9ad1e65..ad3f651 100644 --- a/libstdc++-v3/include/std/array +++ b/libstdc++-v3/include/std/array @@ -253,6 +253,25 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER operator==(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two) { return std::equal(__one.begin(), __one.end(), __two.begin()); } +#if __cpp_lib_three_way_comparison && __cpp_lib_concepts + template<typename _Tp, size_t _Nm> + constexpr __detail::__synth3way_t<_Tp> + operator<=>(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b) + { + if constexpr (_Nm && __is_byte<_Tp>::__value) + return __builtin_memcmp(__a.data(), __b.data(), _Nm) <=> 0; + else + { + for (size_t __i = 0; __i < _Nm; ++__i) + { + auto __c = __detail::__synth3way(__a[__i], __b[__i]); + if (__c != 0) + return __c; + } + } + return strong_ordering::equal; + } +#else template<typename _Tp, std::size_t _Nm> _GLIBCXX20_CONSTEXPR inline bool @@ -285,6 +304,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER inline bool operator>=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two) { return !(__one < __two); } +#endif // three_way_comparison && concepts // Specialized algorithms. template<typename _Tp, std::size_t _Nm> |