Message ID | 20231214010904.1724915-1-jwakely@redhat.com |
---|---|
State | New |
Headers | show |
Series | libstdc++: Optimize std::is_trivially_destructible_v | expand |
Pushed to trunk now. On Thu, 14 Dec 2023 at 01:09, Jonathan Wakely <jwakely@redhat.com> wrote: > > Tested x86_64-linux. > > Does this look right? Can we do it faster, or simplify it? > > -- >8 -- > > This reduces the overhead of using std::is_trivially_destructible_v and > as a result fixes some recent regressions seen with a non-default > GLIBCXX_TESTSUITE_STDS env var: > FAIL: 20_util/variant/87619.cc -std=gnu++20 (test for excess errors) > FAIL: 20_util/variant/87619.cc -std=gnu++23 (test for excess errors) > FAIL: 20_util/variant/87619.cc -std=gnu++26 (test for excess errors) > > libstdc++-v3/ChangeLog: > > * include/std/type_traits (is_trivially_destructible_v): Use > built-in directly when concepts are supported. > * testsuite/20_util/is_trivially_destructible/value_v.cc: New > test. > --- > libstdc++-v3/include/std/type_traits | 19 +++++++++ > .../is_trivially_destructible/value_v.cc | 40 +++++++++++++++++++ > 2 files changed, 59 insertions(+) > create mode 100644 libstdc++-v3/testsuite/20_util/is_trivially_destructible/value_v.cc > > diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits > index 677cd934b94..a0821347676 100644 > --- a/libstdc++-v3/include/std/type_traits > +++ b/libstdc++-v3/include/std/type_traits > @@ -3300,9 +3300,28 @@ template <typename _Tp> > inline constexpr bool is_trivially_move_assignable_v > = __is_trivially_assignable(__add_lval_ref_t<_Tp>, > __add_rval_ref_t<_Tp>); > + > +#if __cpp_concepts > +template <typename _Tp> > + inline constexpr bool is_trivially_destructible_v = false; > + > +template <typename _Tp> > + requires (!is_reference_v<_Tp>) && requires (_Tp& __t) { __t.~_Tp(); } > + inline constexpr bool is_trivially_destructible_v<_Tp> > + = __has_trivial_destructor(_Tp); > +template <typename _Tp> > + inline constexpr bool is_trivially_destructible_v<_Tp&> = true; > +template <typename _Tp> > + inline constexpr bool is_trivially_destructible_v<_Tp&&> = true; > +template <typename _Tp, size_t _Nm> > + inline constexpr bool is_trivially_destructible_v<_Tp[_Nm]> > + = is_trivially_destructible_v<_Tp>; > +#else > template <typename _Tp> > inline constexpr bool is_trivially_destructible_v = > is_trivially_destructible<_Tp>::value; > +#endif > + > template <typename _Tp, typename... _Args> > inline constexpr bool is_nothrow_constructible_v > = __is_nothrow_constructible(_Tp, _Args...); > diff --git a/libstdc++-v3/testsuite/20_util/is_trivially_destructible/value_v.cc b/libstdc++-v3/testsuite/20_util/is_trivially_destructible/value_v.cc > new file mode 100644 > index 00000000000..7db098a2c4d > --- /dev/null > +++ b/libstdc++-v3/testsuite/20_util/is_trivially_destructible/value_v.cc > @@ -0,0 +1,40 @@ > +// { dg-do compile { target c++17 } } > +#include <type_traits> > +#include <testsuite_tr1.h> > + > +template<typename T> > +constexpr void test_cv() > +{ > + static_assert(std::is_trivially_destructible_v<const T> > + == std::is_trivially_destructible_v<T>); > + static_assert(std::is_trivially_destructible_v<volatile T> > + == std::is_trivially_destructible_v<T>); > + static_assert(std::is_trivially_destructible_v<const volatile T> > + == std::is_trivially_destructible_v<T>); > +} > + > +template<typename T, bool Expected> > +void test() > +{ > + static_assert(std::is_trivially_destructible_v<T> == Expected); > + test_cv<T>(); > +} > + > +void test01() > +{ > + using namespace __gnu_test; > + > + test<int, true>(); > + test<int&, true>(); > + test<int&&, true>(); > + test<int[1], true>(); > + test<TType, true>(); > + test<TType[1], true>(); > + test<PODType, true>(); > + test<PODType[1], true>(); > + test<NType, false>(); > + test<SLType, false>(); > + test<int(), false>(); > + test<void, false>(); > + test<int[], false>(); > +} > -- > 2.43.0 >
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits index 677cd934b94..a0821347676 100644 --- a/libstdc++-v3/include/std/type_traits +++ b/libstdc++-v3/include/std/type_traits @@ -3300,9 +3300,28 @@ template <typename _Tp> inline constexpr bool is_trivially_move_assignable_v = __is_trivially_assignable(__add_lval_ref_t<_Tp>, __add_rval_ref_t<_Tp>); + +#if __cpp_concepts +template <typename _Tp> + inline constexpr bool is_trivially_destructible_v = false; + +template <typename _Tp> + requires (!is_reference_v<_Tp>) && requires (_Tp& __t) { __t.~_Tp(); } + inline constexpr bool is_trivially_destructible_v<_Tp> + = __has_trivial_destructor(_Tp); +template <typename _Tp> + inline constexpr bool is_trivially_destructible_v<_Tp&> = true; +template <typename _Tp> + inline constexpr bool is_trivially_destructible_v<_Tp&&> = true; +template <typename _Tp, size_t _Nm> + inline constexpr bool is_trivially_destructible_v<_Tp[_Nm]> + = is_trivially_destructible_v<_Tp>; +#else template <typename _Tp> inline constexpr bool is_trivially_destructible_v = is_trivially_destructible<_Tp>::value; +#endif + template <typename _Tp, typename... _Args> inline constexpr bool is_nothrow_constructible_v = __is_nothrow_constructible(_Tp, _Args...); diff --git a/libstdc++-v3/testsuite/20_util/is_trivially_destructible/value_v.cc b/libstdc++-v3/testsuite/20_util/is_trivially_destructible/value_v.cc new file mode 100644 index 00000000000..7db098a2c4d --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/is_trivially_destructible/value_v.cc @@ -0,0 +1,40 @@ +// { dg-do compile { target c++17 } } +#include <type_traits> +#include <testsuite_tr1.h> + +template<typename T> +constexpr void test_cv() +{ + static_assert(std::is_trivially_destructible_v<const T> + == std::is_trivially_destructible_v<T>); + static_assert(std::is_trivially_destructible_v<volatile T> + == std::is_trivially_destructible_v<T>); + static_assert(std::is_trivially_destructible_v<const volatile T> + == std::is_trivially_destructible_v<T>); +} + +template<typename T, bool Expected> +void test() +{ + static_assert(std::is_trivially_destructible_v<T> == Expected); + test_cv<T>(); +} + +void test01() +{ + using namespace __gnu_test; + + test<int, true>(); + test<int&, true>(); + test<int&&, true>(); + test<int[1], true>(); + test<TType, true>(); + test<TType[1], true>(); + test<PODType, true>(); + test<PODType[1], true>(); + test<NType, false>(); + test<SLType, false>(); + test<int(), false>(); + test<void, false>(); + test<int[], false>(); +}