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author | Jonathan Wakely <jwakely@redhat.com> | 2022-05-19 13:26:49 +0100 |
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committer | Jonathan Wakely <jwakely@redhat.com> | 2022-05-19 15:30:56 +0100 |
commit | f13f9c99dbee9c495955a430dd10bdb24a16f24a (patch) | |
tree | 4dac810cf67f6bac7e59ce83be736453bb74e1d7 | |
parent | 060173dd73fcaf0767215f9d989ad064e2d5fe2a (diff) | |
download | gcc-f13f9c99dbee9c495955a430dd10bdb24a16f24a.zip gcc-f13f9c99dbee9c495955a430dd10bdb24a16f24a.tar.gz gcc-f13f9c99dbee9c495955a430dd10bdb24a16f24a.tar.bz2 |
libstdc++: Implement LWG 3683 for pmr::polymorphic_allocator
This issue has recently been moved to Tentatively Ready, and seems
uncontroversial. This allows equality comparison with types that are
convertible to pmr::polymorphic_allocator, which fail deduction for the
existing equality operator.
libstdc++-v3/ChangeLog:
* include/std/memory_resource (polymorphic_allocator): Add
non-template equality operator, as proposed for LWG 3683.
* testsuite/20_util/polymorphic_allocator/lwg3683.cc: New test.
-rw-r--r-- | libstdc++-v3/include/std/memory_resource | 16 | ||||
-rw-r--r-- | libstdc++-v3/testsuite/20_util/polymorphic_allocator/lwg3683.cc | 13 |
2 files changed, 29 insertions, 0 deletions
diff --git a/libstdc++-v3/include/std/memory_resource b/libstdc++-v3/include/std/memory_resource index 88e8abd..745422a 100644 --- a/libstdc++-v3/include/std/memory_resource +++ b/libstdc++-v3/include/std/memory_resource @@ -356,6 +356,22 @@ namespace pmr __attribute__((__returns_nonnull__)) { return _M_resource; } + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 3683. operator== for polymorphic_allocator cannot deduce template arg + [[nodiscard]] + friend bool + operator==(const polymorphic_allocator& __a, + const polymorphic_allocator& __b) noexcept + { return *__a.resource() == *__b.resource(); } + +#if __cpp_impl_three_way_comparison < 201907L + [[nodiscard]] + friend bool + operator!=(const polymorphic_allocator& __a, + const polymorphic_allocator& __b) noexcept + { return !(__a == __b); } +#endif + private: #if ! __cpp_lib_make_obj_using_allocator using __uses_alloc1_ = __uses_alloc1<polymorphic_allocator>; diff --git a/libstdc++-v3/testsuite/20_util/polymorphic_allocator/lwg3683.cc b/libstdc++-v3/testsuite/20_util/polymorphic_allocator/lwg3683.cc new file mode 100644 index 0000000..acc91f5 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/polymorphic_allocator/lwg3683.cc @@ -0,0 +1,13 @@ +// { dg-do compile { target c++17 } } + +#include <memory_resource> + +bool +test_lwg3683(const std::pmr::polymorphic_allocator<int>& a) +{ + if (a == std::pmr::get_default_resource()) + return true; + if (std::pmr::get_default_resource() != a) + return false; + throw a; +} |