diff options
author | Jonathan Wakely <jwakely@redhat.com> | 2018-10-02 15:00:50 +0100 |
---|---|---|
committer | Jonathan Wakely <redi@gcc.gnu.org> | 2018-10-02 15:00:50 +0100 |
commit | 469218a3f9b8f72b38d82dd978ec231ab3de14ef (patch) | |
tree | a69a6ba487c13ad4ce8f595f485a8f2f0daefdf1 /libstdc++-v3 | |
parent | f512bf3ee95914b30ba67f80ca42a72ec630738f (diff) | |
download | gcc-469218a3f9b8f72b38d82dd978ec231ab3de14ef.zip gcc-469218a3f9b8f72b38d82dd978ec231ab3de14ef.tar.gz gcc-469218a3f9b8f72b38d82dd978ec231ab3de14ef.tar.bz2 |
Avoid redundant runtime checks in std::visit
Calling std::get will check some static assertions and also do a runtime
check for a valid index before calling __detail::__variant::__get. The
std::visit function already handles the case where any variant has an
invalid index, so __get can be used directly in __visit_invoke.
* include/std/variant (__gen_vtable_impl::__visit_invoke): Call __get
directly instead of get, as caller ensures correct index is used.
(holds_alternative, get, get_if): Remove redundant inline specifiers.
(_VARIANT_RELATION_FUNCTION_TEMPLATE): Likewise.
From-SVN: r264786
Diffstat (limited to 'libstdc++-v3')
-rw-r--r-- | libstdc++-v3/ChangeLog | 7 | ||||
-rw-r--r-- | libstdc++-v3/include/std/variant | 34 |
2 files changed, 23 insertions, 18 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index c513551..388ae9d 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,10 @@ +2018-10-02 Jonathan Wakely <jwakely@redhat.com> + + * include/std/variant (__gen_vtable_impl::__visit_invoke): Call __get + directly instead of get, as caller ensures correct index is used. + (holds_alternative, get, get_if): Remove redundant inline specifiers. + (_VARIANT_RELATION_FUNCTION_TEMPLATE): Likewise. + 2018-10-02 Joseph Myers <joseph@codesourcery.com> * testsuite/lib/libstdc++.exp (libstdc++_init): Use diff --git a/libstdc++-v3/include/std/variant b/libstdc++-v3/include/std/variant index 9289eef..ff340cf 100644 --- a/libstdc++-v3/include/std/variant +++ b/libstdc++-v3/include/std/variant @@ -811,9 +811,8 @@ namespace __variant { using _Alternative = variant_alternative_t<__index, _Next>; __element = __gen_vtable_impl< - remove_reference_t< - decltype(__element)>, tuple<_Variants...>, - std::index_sequence<__indices..., __index>>::_S_apply(); + remove_reference_t<decltype(__element)>, tuple<_Variants...>, + std::index_sequence<__indices..., __index>>::_S_apply(); } }; @@ -826,11 +825,11 @@ namespace __variant using _Array_type = _Multi_array<_Result_type (*)(_Visitor&&, _Variants...)>; - decltype(auto) - static constexpr __visit_invoke(_Visitor&& __visitor, _Variants... __vars) + static constexpr decltype(auto) + __visit_invoke(_Visitor&& __visitor, _Variants... __vars) { return std::__invoke(std::forward<_Visitor>(__visitor), - std::get<__indices>(std::forward<_Variants>(__vars))...); + __variant::__get<__indices>(std::forward<_Variants>(__vars))...); } static constexpr auto @@ -871,8 +870,8 @@ namespace __variant } // namespace __detail template<typename _Tp, typename... _Types> - inline constexpr bool holds_alternative(const variant<_Types...>& __v) - noexcept + constexpr bool + holds_alternative(const variant<_Types...>& __v) noexcept { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, "T should occur for exactly once in alternatives"); @@ -880,7 +879,7 @@ namespace __variant } template<typename _Tp, typename... _Types> - constexpr inline _Tp& get(variant<_Types...>& __v) + constexpr _Tp& get(variant<_Types...>& __v) { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, "T should occur for exactly once in alternatives"); @@ -889,7 +888,7 @@ namespace __variant } template<typename _Tp, typename... _Types> - constexpr inline _Tp&& get(variant<_Types...>&& __v) + constexpr _Tp&& get(variant<_Types...>&& __v) { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, "T should occur for exactly once in alternatives"); @@ -899,7 +898,7 @@ namespace __variant } template<typename _Tp, typename... _Types> - constexpr inline const _Tp& get(const variant<_Types...>& __v) + constexpr const _Tp& get(const variant<_Types...>& __v) { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, "T should occur for exactly once in alternatives"); @@ -908,7 +907,7 @@ namespace __variant } template<typename _Tp, typename... _Types> - constexpr inline const _Tp&& get(const variant<_Types...>&& __v) + constexpr const _Tp&& get(const variant<_Types...>&& __v) { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, "T should occur for exactly once in alternatives"); @@ -918,8 +917,7 @@ namespace __variant } template<size_t _Np, typename... _Types> - constexpr inline - add_pointer_t<variant_alternative_t<_Np, variant<_Types...>>> + constexpr add_pointer_t<variant_alternative_t<_Np, variant<_Types...>>> get_if(variant<_Types...>* __ptr) noexcept { using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>; @@ -932,7 +930,7 @@ namespace __variant } template<size_t _Np, typename... _Types> - constexpr inline + constexpr add_pointer_t<const variant_alternative_t<_Np, variant<_Types...>>> get_if(const variant<_Types...>* __ptr) noexcept { @@ -946,7 +944,7 @@ namespace __variant } template<typename _Tp, typename... _Types> - constexpr inline add_pointer_t<_Tp> + constexpr add_pointer_t<_Tp> get_if(variant<_Types...>* __ptr) noexcept { static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>, @@ -957,7 +955,7 @@ namespace __variant } template<typename _Tp, typename... _Types> - constexpr inline add_pointer_t<const _Tp> + constexpr add_pointer_t<const _Tp> get_if(const variant<_Types...>* __ptr) noexcept { @@ -1277,7 +1275,7 @@ namespace __variant { &__detail::__variant::__erased_##__NAME< \ const variant&, __indices>... }; \ template<size_t... __indices> \ - constexpr inline bool \ + constexpr bool \ _M_##__NAME(const variant& __rhs, \ std::index_sequence<__indices...>) const \ { \ |