>From other side, it would be fairly easy to add another _TrivlalEmpty specialization for __func_handle, that would be generated under p3117r1 conditions, which I do not like, as they do not make even *it on same iterator sable for the Obfuscating symbol. I would go instead with is_empty_v<F> && copyable<F> && trivially_copyable<F>, and have [[no_unique_address]] F _M_fun member.
>From that perspective, think we should land this patch regardless. Even if we would like to do a follow up aligned with additional specialization that is aligned the paper. Regards, Tomasz On Fri, Nov 14, 2025 at 3:37 PM Tomasz Kaminski <[email protected]> wrote: > > > On Fri, Nov 14, 2025 at 2:18 PM Hewill Kang <[email protected]> wrote: > >> I can't help but wonder, if this patch can't optimize for lambdas (users >> generally don't explicitly spell `static`), then I don't see much point in >> this optimization. >> > Then they should start to. if they want to get optimizations. For most > cases it really does not matter, as the compiler inlines and removes all > iterators. > The only relevant cases here are erasing view (storing in any_view) or > relying on range being borrowed. > >> >> I think the case of `Obfuscate` is unlikely to occur. The view class will >> move the original object to the `movable_box` via `std::move(fun)`, so >> `this` pointer has already changed. >> > I believe the standard requires it to work, so breaking it would be > invalid optimization. > >> >> If we could actually create such a pretentious functor with a disgusting >> operator(), I think the standard has every reason not to care about it. >> >> Therefore, after thinking about it, I think we should perhaps follow >> p3117r1 and use `is_empty_v<F> && is_trivially_default_constructible_v<F> >> && is_trivially_destructible_v<F>` to optimize lambda. Because that is >> undoubtedly the most common use case (and the most worthy of >> optimization). This is something this patch should be interested in. >> > Unless the standard gives permission to do so, I do not think such change > is possible. > >> >> Tomasz Kaminski <[email protected]> 於 2025年11月14日 週五 下午5:36寫道： >> >>> >>> >>> On Fri, Nov 14, 2025 at 10:24 AM Hewill Kang <[email protected]> wrote: >>> >>>> Yes, I do not think anything in standard clearly states the that >>>>> following is >>>>> allowed to fail: >>>>> struct Obfuscate >>>>> { >>>>> int operator()(int x) const >>>>> { return x + static_assert<unintptr_t>(this); } >>>>> }; >>>> >>>> >>>>> std::vector<int> v{1, 2, 3, 4, 5}; >>>>> auto tv = v | std::transform(Obfuscate{}); >>>>> VERIFY( ranges::equal(tv, tv) ); >>>>> But storing an empty object in an iterator will break. >>>> >>>> >>>> This is a very good observation, so recreating empty objects is still >>>> problematic. >>>> It also seems to suggest that >>>> https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2024/p3117r1.html (most >>>> likely a follow-up to this patch) and >>>> https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2025/p3705r1.html >>>> might have issues with this. >>>> For example, `operator()` uses `this` or `operator==` uses `this`. >>>> >>> Yes, static operator() is bulletproof way of ensuring that it does not >>> depend on object identity, >>> even if the object itself is not empty. We do not need to use >>> heuristics based on size anymore. >>> >>>> >>>> Tomasz Kaminski <[email protected]> 於 2025年11月14日 週五 下午2:36寫道： >>>> >>>>> >>>>> >>>>> On Fri, Nov 14, 2025 at 4:16 AM Patrick Palka <[email protected]> >>>>> wrote: >>>>> >>>>>> On Thu, 13 Nov 2025, Tomasz Kamiński wrote: >>>>>> >>>>>> > The iterators for transform views (views::transform, >>>>>> views::zip_transform, >>>>>> > and views::adjacent_transform) now store a __detail::__func_handle >>>>>> instead >>>>>> > of a pointer to the view object (_M_parent). >>>>>> > >>>>>> > The behavior of the __func_handle specialization depends on the >>>>>> _FunctorType >>>>>> > template parameter: >>>>>> > * _FunctionPtr: Used if the functor is a function pointer. The >>>>>> pointer is >>>>>> > stored directly in __func_handle and the iterator, avoiding double >>>>>> > indirection through a pointer to the function pointer. >>>>>> > * _MemberPointer: Used for data or function member pointers. This >>>>>> behaves >>>>>> > similarly to _FunctionPtr, but uses __invoke for invocations. >>>>>> > * _StaticOperator: Used if the operator() selected by overload >>>>>> resolution >>>>>> > for the iterator reference is static. In this case, >>>>>> __func_handle is empty, >>>>>> > reducing the iterator size. >>>>>> > * _Statefull: Used for all remaining cases. __func_handle stores a >>>>>> pointer >>>>>> > to the functor object stored within the view. Only for this >>>>>> specialization is >>>>>> > the cv-qualification of the functor template parameter (_Fn) >>>>>> relevant, and >>>>>> > both const and mutable specializations are generated. >>>>>> >>>>>> FWIW it's spelled 'stateful' with just one l. >>>>>> >>>>>> I guess you concluded that this optimization is unsafe for empty >>>>>> objects >>>>>> with non-static operator()? >>>>>> >>>>> Yes, I do not think anything in standard clearly states the that >>>>> following is >>>>> allowed to fail: >>>>> struct Obfuscate >>>>> { >>>>> int operator()(int x) const >>>>> { return x + static_assert<unintptr_t>(this); } >>>>> }; >>>>> >>>>> std::vector<int> v{1, 2, 3, 4, 5}; >>>>> auto tv = v | std::transform(Obfuscate{}); >>>>> VERIFY( ranges::equal(tv, tv) ); >>>>> >>>>> But storing an empty object in an iterator will break. >>>>> >>>>> >>>>>> > >>>>>> > As a consequence of these changes, the iterators of transform views >>>>>> no longer >>>>>> > depend on the view object when __func_handle is specialized for >>>>>> values other >>>>>> > than _Statefull. The corresponding views are not marked as >>>>>> borrowed_range, >>>>>> > as they are not marked as such in the standard. >>>>>> > >>>>>> > Storing function member pointers directly increases the iterator >>>>>> size in that >>>>>> > specific case, but this is deemed beneficial for consistent >>>>>> treatment of >>>>>> > function and data member pointers. >>>>>> > >>>>>> > To avoid materializing temporaries when the underlying iterator(s) >>>>>> return a >>>>>> > prvalue, the _M_call_deref and _M_call_subscript methods of >>>>>> __func_handle are >>>>>> > defined to accept the iterator(s), which are then dereferenced as >>>>>> arguments >>>>>> > of the functor. >>>>>> > >>>>>> > Using _Fd::operator()(*__iters...) inside requires expression is >>>>>> only >>>>>> > supported since clang-20, however at the point of GCC-16 release, >>>>>> clang-22 >>>>>> > should be already available. >>>>>> > >>>>>> > libstdc++-v3/ChangeLog: >>>>>> > >>>>>> > * include/std/ranges (__detail::__func_handle) >>>>>> > (__detail::func_handle_t): Define. >>>>>> > (transform_view::_Iterator, zip_transform_view::_Iterator) >>>>>> > (adjacent_tranform_view::_Iterator): Replace pointer to view >>>>>> > (_M_parent) with pointer to functor (_M_fun). Update >>>>>> constructors >>>>>> > to cosntruct _M_fun from *__parent->_M_fun. Define operator* >>>>>> and >>>>>> > operator[] in terms of _M_call_deref and _M_call_subscript. >>>>>> > * testsuite/std/ranges/adaptors/adjacent_transform/1.cc: New >>>>>> tests. >>>>>> > * testsuite/std/ranges/adaptors/transform.cc: New tests. >>>>>> > * testsuite/std/ranges/zip_transform/1.cc: New tests. >>>>>> > --- >>>>>> > Tested transform view files locally. More testing in progress. >>>>>> > >>>>>> > libstdc++-v3/include/std/ranges | 214 >>>>>> +++++++++++++++--- >>>>>> > .../ranges/adaptors/adjacent_transform/1.cc | 97 ++++++++ >>>>>> > .../std/ranges/adaptors/transform.cc | 118 +++++++++- >>>>>> > .../testsuite/std/ranges/zip_transform/1.cc | 101 +++++++++ >>>>>> > 4 files changed, 493 insertions(+), 37 deletions(-) >>>>>> > >>>>>> > diff --git a/libstdc++-v3/include/std/ranges >>>>>> b/libstdc++-v3/include/std/ranges >>>>>> > index ae57b9a0809..28b4f1d2b90 100644 >>>>>> > --- a/libstdc++-v3/include/std/ranges >>>>>> > +++ b/libstdc++-v3/include/std/ranges >>>>>> > @@ -286,6 +286,138 @@ namespace ranges >>>>>> > operator->() const noexcept >>>>>> > { return std::__addressof(_M_value); } >>>>>> > }; >>>>>> > + >>>>>> > + enum class _FunctorType >>>>>> > + { >>>>>> > + _FunctionPtr, >>>>>> > + _MemberPtr, >>>>>> > + _StaticOperator, >>>>>> > + _Statefull, >>>>>> > + }; >>>>>> > + >>>>>> > + template<typename _Fn, _FunctorType __ft> >>>>>> > + struct __func_handle >>>>>> > + { >>>>>> > + __func_handle() = default; >>>>>> > + >>>>>> > + constexpr explicit >>>>>> > + __func_handle(_Fn& __func) noexcept >>>>>> > + : _M_ptr(std::addressof(__func)) >>>>>> > + { } >>>>>> > + >>>>>> > + template<typename _Un> >>>>>> > + requires (!is_const_v<_Un>) && is_same_v<const _Un, _Fn> >>>>>> > + constexpr explicit >>>>>> > + __func_handle(__func_handle<_Un, __ft> __other) noexcept >>>>>> > + : _M_ptr(__other._M_ptr) >>>>>> > + { } >>>>>> > + >>>>>> > + template<typename... _Iters> >>>>>> > + constexpr decltype(auto) >>>>>> > + _M_call_deref(const _Iters&... __iters) const >>>>>> > + noexcept(noexcept((*_M_ptr)(*__iters...))) >>>>>> > + { return (*_M_ptr)(*__iters...); } >>>>>> > + >>>>>> > + template<typename _DistType, typename... _Iters> >>>>>> > + constexpr decltype(auto) >>>>>> > + _M_call_subscript(const _DistType __n, const _Iters&... >>>>>> __iters) const >>>>>> > + >>>>>> >>>>>> noexcept(noexcept((*_M_ptr)(__iters[iter_difference_t<_Iters>(__n)]...))) >>>>>> > + { return >>>>>> (*_M_ptr)(__iters[iter_difference_t<_Iters>(__n)]...); } >>>>>> > + >>>>>> > + private: >>>>>> > + _Fn* _M_ptr = nullptr; >>>>>> > + >>>>>> > + template<typename, _FunctorType> >>>>>> > + friend struct __func_handle; >>>>>> > + }; >>>>>> > + >>>>>> > + template<typename _Fn> >>>>>> > + struct __func_handle<_Fn, _FunctorType::_FunctionPtr> >>>>>> > + { >>>>>> > + __func_handle() = default; >>>>>> > + >>>>>> > + constexpr explicit >>>>>> > + __func_handle(_Fn __func) noexcept >>>>>> > + : _M_ptr(__func) >>>>>> > + { } >>>>>> > + >>>>>> > + template<typename... _Iters> >>>>>> > + constexpr decltype(auto) >>>>>> > + _M_call_deref(const _Iters&... __iters) const >>>>>> > + noexcept(noexcept(_M_ptr(*__iters...))) >>>>>> > + { return _M_ptr(*__iters...); } >>>>>> > + >>>>>> > + template<typename _DistType, typename... _Iters> >>>>>> > + constexpr decltype(auto) >>>>>> > + _M_call_subscript(const _DistType __n, const _Iters&... >>>>>> __iters) const >>>>>> > + >>>>>> noexcept(noexcept(_M_ptr(__iters[iter_difference_t<_Iters>(__n)]...))) >>>>>> > + { return >>>>>> _M_ptr(__iters[iter_difference_t<_Iters>(__n)]...); } >>>>>> > + >>>>>> > + private: >>>>>> > + _Fn _M_ptr = nullptr; >>>>>> > + }; >>>>>> > + >>>>>> > + template<typename _Fn> >>>>>> > + struct __func_handle<_Fn, _FunctorType::_MemberPtr> >>>>>> > + { >>>>>> > + __func_handle() = default; >>>>>> > + >>>>>> > + constexpr explicit >>>>>> > + __func_handle(_Fn __func) noexcept >>>>>> > + : _M_ptr(__func) >>>>>> > + {} >>>>>> > + >>>>>> > + template<typename... _Iters> >>>>>> > + constexpr decltype(auto) >>>>>> > + _M_call_deref(const _Iters&... __iters) const >>>>>> > + noexcept(noexcept(std::__invoke(_M_ptr, *__iters...))) >>>>>> > + { return std::__invoke(_M_ptr, *__iters...); } >>>>>> > + >>>>>> > + template<typename _DistType, typename... _Iters> >>>>>> > + constexpr decltype(auto) >>>>>> > + _M_call_subscript(const _DistType __n, const _Iters&... >>>>>> __iters) const >>>>>> > + noexcept(noexcept(std::__invoke(_M_ptr, >>>>>> __iters[iter_difference_t<_Iters>(__n)]...))) >>>>>> > + { return std::__invoke(_M_ptr, >>>>>> __iters[iter_difference_t<_Iters>(__n)]...); } >>>>>> > + >>>>>> > + private: >>>>>> > + _Fn _M_ptr = nullptr; >>>>>> > + }; >>>>>> > + >>>>>> > + template<typename _Fn> >>>>>> > + struct __func_handle<_Fn, _FunctorType::_StaticOperator> >>>>>> > + { >>>>>> > + __func_handle() = default; >>>>>> > + >>>>>> > + constexpr explicit >>>>>> > + __func_handle(const _Fn&) noexcept >>>>>> > + {} >>>>>> > + >>>>>> > + template<typename... _Iters> >>>>>> > + static constexpr decltype(auto) >>>>>> > + _M_call_deref(const _Iters&... __iters) >>>>>> > + noexcept(noexcept(_Fn::operator()(*__iters...))) >>>>>> > + { return _Fn::operator()(*__iters...); } >>>>>> > + >>>>>> > + template<typename _DistType, typename... _Iters> >>>>>> > + static constexpr decltype(auto) >>>>>> > + _M_call_subscript(_DistType __n, const _Iters&... __iters) >>>>>> > + >>>>>> >>>>>> noexcept(noexcept(_Fn::operator()(__iters[iter_difference_t<_Iters>(__n)]...))) >>>>>> > + { return >>>>>> _Fn::operator()(__iters[iter_difference_t<_Iters>(__n)]...); } >>>>>> > + }; >>>>>> > + >>>>>> > + template<typename _Fn, typename... _Iters> >>>>>> > + using __func_handle_t = decltype([] { >>>>>> > + using _Fd = remove_cv_t<_Fn>; >>>>>> > + if constexpr (is_member_pointer_v<_Fd>) >>>>>> > + return __func_handle<_Fd, _FunctorType::_MemberPtr>(); >>>>>> > + else if constexpr >>>>>> (std::is_function_v<remove_pointer_t<_Fd>>) >>>>>> > + return __func_handle<_Fd, _FunctorType::_FunctionPtr>(); >>>>>> > + else if constexpr (requires (const _Iters&... __iters) >>>>>> > + { _Fd::operator()(*__iters...); }) >>>>>> > + return __func_handle<_Fd, >>>>>> _FunctorType::_StaticOperator>(); >>>>>> > + else >>>>>> > + return __func_handle<_Fn, _FunctorType::_Statefull>(); >>>>>> > + }()); >>>>>> > } // namespace __detail >>>>>> > >>>>>> > /// A view that contains exactly one element. >>>>>> > @@ -1874,6 +2006,10 @@ namespace views::__adaptor >>>>>> > private: >>>>>> > using _Parent = __detail::__maybe_const_t<_Const, >>>>>> transform_view>; >>>>>> > using _Base = transform_view::_Base<_Const>; >>>>>> > + using _Base_iter = iterator_t<_Base>; >>>>>> > + using _Func_handle = __detail::__func_handle_t< >>>>>> > + __detail::__maybe_const_t<_Const, >>>>>> _Fp>, >>>>>> > + _Base_iter>; >>>>>> > >>>>>> > static auto >>>>>> > _S_iter_concept() >>>>>> > @@ -1888,10 +2024,8 @@ namespace views::__adaptor >>>>>> > return input_iterator_tag{}; >>>>>> > } >>>>>> > >>>>>> > - using _Base_iter = iterator_t<_Base>; >>>>>> > - >>>>>> > _Base_iter _M_current = _Base_iter(); >>>>>> > - _Parent* _M_parent = nullptr; >>>>>> > + [[no_unique_address]] _Func_handle _M_fun; >>>>>> > >>>>>> > public: >>>>>> > using iterator_concept = decltype(_S_iter_concept()); >>>>>> > @@ -1904,16 +2038,20 @@ namespace views::__adaptor >>>>>> > _Iterator() requires default_initializable<_Base_iter> = >>>>>> default; >>>>>> > >>>>>> > constexpr >>>>>> > - _Iterator(_Parent* __parent, _Base_iter __current) >>>>>> > - : _M_current(std::move(__current)), >>>>>> > - _M_parent(__parent) >>>>>> > + _Iterator(_Func_handle __fun, _Base_iter __current) >>>>>> > + : _M_current(std::move(__current)), _M_fun(__fun) >>>>>> > { } >>>>>> > >>>>>> > + constexpr >>>>>> > + _Iterator(_Parent* __parent, _Base_iter __current) >>>>>> > + : _M_current(std::move(__current)), >>>>>> _M_fun(*__parent->_M_fun) >>>>>> > + {} >>>>>> > + >>>>>> > constexpr >>>>>> > _Iterator(_Iterator<!_Const> __i) >>>>>> > requires _Const >>>>>> > && convertible_to<iterator_t<_Vp>, _Base_iter> >>>>>> > - : _M_current(std::move(__i._M_current)), >>>>>> _M_parent(__i._M_parent) >>>>>> > + : _M_current(std::move(__i._M_current)), >>>>>> _M_fun(__i._M_fun) >>>>>> > { } >>>>>> > >>>>>> > constexpr const _Base_iter& >>>>>> > @@ -1926,8 +2064,8 @@ namespace views::__adaptor >>>>>> > >>>>>> > constexpr decltype(auto) >>>>>> > operator*() const >>>>>> > - noexcept(noexcept(std::__invoke(*_M_parent->_M_fun, >>>>>> *_M_current))) >>>>>> > - { return std::__invoke(*_M_parent->_M_fun, *_M_current); } >>>>>> > + noexcept(noexcept(_M_fun._M_call_deref(_M_current))) >>>>>> > + { return _M_fun._M_call_deref(_M_current); } >>>>>> > >>>>>> > constexpr _Iterator& >>>>>> > operator++() >>>>>> > @@ -1980,7 +2118,7 @@ namespace views::__adaptor >>>>>> > constexpr decltype(auto) >>>>>> > operator[](difference_type __n) const >>>>>> > requires random_access_range<_Base> >>>>>> > - { return std::__invoke(*_M_parent->_M_fun, >>>>>> _M_current[__n]); } >>>>>> > + { return _M_fun._M_call_subscript(__n, _M_current); } >>>>>> > >>>>>> > friend constexpr bool >>>>>> > operator==(const _Iterator& __x, const _Iterator& __y) >>>>>> > @@ -2018,17 +2156,17 @@ namespace views::__adaptor >>>>>> > friend constexpr _Iterator >>>>>> > operator+(_Iterator __i, difference_type __n) >>>>>> > requires random_access_range<_Base> >>>>>> > - { return {__i._M_parent, __i._M_current + __n}; } >>>>>> > + { return {__i._M_fun, __i._M_current + __n}; } >>>>>> > >>>>>> > friend constexpr _Iterator >>>>>> > operator+(difference_type __n, _Iterator __i) >>>>>> > requires random_access_range<_Base> >>>>>> > - { return {__i._M_parent, __i._M_current + __n}; } >>>>>> > + { return {__i._M_fun, __i._M_current + __n}; } >>>>>> > >>>>>> > friend constexpr _Iterator >>>>>> > operator-(_Iterator __i, difference_type __n) >>>>>> > requires random_access_range<_Base> >>>>>> > - { return {__i._M_parent, __i._M_current - __n}; } >>>>>> > + { return {__i._M_fun, __i._M_current - __n}; } >>>>>> > >>>>>> > // _GLIBCXX_RESOLVE_LIB_DEFECTS >>>>>> > // 3483. transform_view::iterator's difference is >>>>>> overconstrained >>>>>> > @@ -5126,13 +5264,21 @@ namespace views::__adaptor >>>>>> > class zip_transform_view<_Fp, _Vs...>::_Iterator : public >>>>>> __iter_cat<_Const> >>>>>> > { >>>>>> > using _Parent = __detail::__maybe_const_t<_Const, >>>>>> zip_transform_view>; >>>>>> > + using _Fun_handle = __detail::__func_handle_t< >>>>>> > + __detail::__maybe_const_t<_Const, _Fp>, >>>>>> > + >>>>>> iterator_t<__detail::__maybe_const_t<_Const, _Vs>>...>; >>>>>> > >>>>>> > - _Parent* _M_parent = nullptr; >>>>>> > + [[no_unique_address]] _Fun_handle _M_fun; >>>>>> > __ziperator<_Const> _M_inner; >>>>>> > >>>>>> > + constexpr >>>>>> > + _Iterator(_Fun_handle __fun, __ziperator<_Const> __inner) >>>>>> > + : _M_fun(__fun), _M_inner(std::move(__inner)) >>>>>> > + { } >>>>>> > + >>>>>> > constexpr >>>>>> > _Iterator(_Parent& __parent, __ziperator<_Const> __inner) >>>>>> > - : _M_parent(std::__addressof(__parent)), >>>>>> _M_inner(std::move(__inner)) >>>>>> > + : _M_fun(*__parent._M_fun), _M_inner(std::move(__inner)) >>>>>> > { } >>>>>> > >>>>>> > friend class zip_transform_view; >>>>>> > @@ -5150,14 +5296,14 @@ namespace views::__adaptor >>>>>> > constexpr >>>>>> > _Iterator(_Iterator<!_Const> __i) >>>>>> > requires _Const && convertible_to<__ziperator<false>, >>>>>> __ziperator<_Const>> >>>>>> > - : _M_parent(__i._M_parent), _M_inner(std::move(__i._M_inner)) >>>>>> > + : _M_fun(__i._M_fun), _M_inner(std::move(__i._M_inner)) >>>>>> > { } >>>>>> > >>>>>> > constexpr decltype(auto) >>>>>> > operator*() const >>>>>> > { >>>>>> > return std::apply([&](const auto&... __iters) -> >>>>>> decltype(auto) { >>>>>> > - return std::__invoke(*_M_parent->_M_fun, *__iters...); >>>>>> > + return _M_fun._M_call_deref(__iters...); >>>>>> > }, _M_inner._M_current); >>>>>> > } >>>>>> > >>>>>> > @@ -5213,7 +5359,7 @@ namespace views::__adaptor >>>>>> > operator[](difference_type __n) const requires >>>>>> random_access_range<_Base<_Const>> >>>>>> > { >>>>>> > return std::apply([&]<typename... _Is>(const _Is&... >>>>>> __iters) -> decltype(auto) { >>>>>> > - return std::__invoke(*_M_parent->_M_fun, >>>>>> __iters[iter_difference_t<_Is>(__n)]...); >>>>>> > + return _M_fun._M_call_subscript(__n, __iters...); >>>>>> > }, _M_inner._M_current); >>>>>> > } >>>>>> > >>>>>> > @@ -5230,17 +5376,17 @@ namespace views::__adaptor >>>>>> > friend constexpr _Iterator >>>>>> > operator+(const _Iterator& __i, difference_type __n) >>>>>> > requires random_access_range<_Base<_Const>> >>>>>> > - { return _Iterator(*__i._M_parent, __i._M_inner + __n); } >>>>>> > + { return _Iterator(__i._M_fun, __i._M_inner + __n); } >>>>>> > >>>>>> > friend constexpr _Iterator >>>>>> > operator+(difference_type __n, const _Iterator& __i) >>>>>> > requires random_access_range<_Base<_Const>> >>>>>> > - { return _Iterator(*__i._M_parent, __i._M_inner + __n); } >>>>>> > + { return _Iterator(__i._M_fun, __i._M_inner + __n); } >>>>>> > >>>>>> > friend constexpr _Iterator >>>>>> > operator-(const _Iterator& __i, difference_type __n) >>>>>> > requires random_access_range<_Base<_Const>> >>>>>> > - { return _Iterator(*__i._M_parent, __i._M_inner - __n); } >>>>>> > + { return _Iterator(__i._M_fun, __i._M_inner - __n); } >>>>>> > >>>>>> > friend constexpr difference_type >>>>>> > operator-(const _Iterator& __x, const _Iterator& __y) >>>>>> > @@ -5807,13 +5953,23 @@ namespace views::__adaptor >>>>>> > { >>>>>> > using _Parent = __detail::__maybe_const_t<_Const, >>>>>> adjacent_transform_view>; >>>>>> > using _Base = __detail::__maybe_const_t<_Const, _Vp>; >>>>>> > + using _Fun_handle = decltype([]<size_t... >>>>>> _Ids>(std::index_sequence<_Ids...>) { >>>>>> > + return __detail::__func_handle_t< >>>>>> > + __detail::__maybe_const_t<_Const, >>>>>> _Fp>, >>>>>> > + >>>>>> iterator_t<__detail::__maybe_const_t<_Const || (_Ids < 0u), _Vp>>...>(); >>>>>> >>>>>> Maybe '(_Ids, _Const)' would be a little less cryptic than >>>>>> '_Const || (_Ids < 0u)'? >>>>>> >>>>> Yes, that is major improvement. >>>>> >>>>>> Besides that looks good! >>>>>> >>>>>> > + }(make_index_sequence<_Nm>())); >>>>>> > >>>>>> > - _Parent* _M_parent = nullptr; >>>>>> > + [[no_unique_address]] _Fun_handle _M_fun; >>>>>> > _InnerIter<_Const> _M_inner; >>>>>> > >>>>>> > + constexpr >>>>>> > + _Iterator(_Fun_handle __fun, _InnerIter<_Const> __inner) >>>>>> > + : _M_fun(__fun), _M_inner(std::move(__inner)) >>>>>> > + { } >>>>>> > + >>>>>> > constexpr >>>>>> > _Iterator(_Parent& __parent, _InnerIter<_Const> __inner) >>>>>> > - : _M_parent(std::__addressof(__parent)), >>>>>> _M_inner(std::move(__inner)) >>>>>> > + : _M_fun(*__parent._M_fun), _M_inner(std::move(__inner)) >>>>>> > { } >>>>>> > >>>>>> > static auto >>>>>> > @@ -5854,14 +6010,14 @@ namespace views::__adaptor >>>>>> > constexpr >>>>>> > _Iterator(_Iterator<!_Const> __i) >>>>>> > requires _Const && convertible_to<_InnerIter<false>, >>>>>> _InnerIter<_Const>> >>>>>> > - : _M_parent(__i._M_parent), _M_inner(std::move(__i._M_inner)) >>>>>> > + : _M_fun(__i._M_fun), _M_inner(std::move(__i._M_inner)) >>>>>> > { } >>>>>> > >>>>>> > constexpr decltype(auto) >>>>>> > operator*() const >>>>>> > { >>>>>> > return std::apply([&](const auto&... __iters) -> >>>>>> decltype(auto) { >>>>>> > - return std::__invoke(*_M_parent->_M_fun, *__iters...); >>>>>> > + return _M_fun._M_call_deref(__iters...); >>>>>> > }, _M_inner._M_current); >>>>>> > } >>>>>> > >>>>>> > @@ -5913,7 +6069,7 @@ namespace views::__adaptor >>>>>> > operator[](difference_type __n) const requires >>>>>> random_access_range<_Base> >>>>>> > { >>>>>> > return std::apply([&](const auto&... __iters) -> >>>>>> decltype(auto) { >>>>>> > - return std::__invoke(*_M_parent->_M_fun, __iters[__n]...); >>>>>> > + return _M_fun._M_call_subscript(__n, __iters...); >>>>>> > }, _M_inner._M_current); >>>>>> > } >>>>>> > >>>>>> > @@ -5950,17 +6106,17 @@ namespace views::__adaptor >>>>>> > friend constexpr _Iterator >>>>>> > operator+(const _Iterator& __i, difference_type __n) >>>>>> > requires random_access_range<_Base> >>>>>> > - { return _Iterator(*__i._M_parent, __i._M_inner + __n); } >>>>>> > + { return _Iterator(__i._M_fun, __i._M_inner + __n); } >>>>>> > >>>>>> > friend constexpr _Iterator >>>>>> > operator+(difference_type __n, const _Iterator& __i) >>>>>> > requires random_access_range<_Base> >>>>>> > - { return _Iterator(*__i._M_parent, __i._M_inner + __n); } >>>>>> > + { return _Iterator(__i._M_fun, __i._M_inner + __n); } >>>>>> > >>>>>> > friend constexpr _Iterator >>>>>> > operator-(const _Iterator& __i, difference_type __n) >>>>>> > requires random_access_range<_Base> >>>>>> > - { return _Iterator(*__i._M_parent, __i._M_inner - __n); } >>>>>> > + { return _Iterator(__i._M_fun, __i._M_inner - __n); } >>>>>> > >>>>>> > friend constexpr difference_type >>>>>> > operator-(const _Iterator& __x, const _Iterator& __y) >>>>>> > diff --git >>>>>> a/libstdc++-v3/testsuite/std/ranges/adaptors/adjacent_transform/1.cc >>>>>> b/libstdc++-v3/testsuite/std/ranges/adaptors/adjacent_transform/1.cc >>>>>> > index 772e4b3b6a0..1667c6250c5 100644 >>>>>> > --- >>>>>> a/libstdc++-v3/testsuite/std/ranges/adaptors/adjacent_transform/1.cc >>>>>> > +++ >>>>>> b/libstdc++-v3/testsuite/std/ranges/adaptors/adjacent_transform/1.cc >>>>>> > @@ -113,6 +113,97 @@ test04() >>>>>> > static_assert( requires { x | >>>>>> views::pairwise_transform(move_only{}); } ); >>>>>> > } >>>>>> > >>>>>> > +struct X >>>>>> > +{ >>>>>> > + int i,j; >>>>>> > + constexpr int combine(X o) const >>>>>> > + { return i + o.j; } >>>>>> > +}; >>>>>> > + >>>>>> > +template<size_t FuncSize, typename Fn> >>>>>> > +constexpr bool >>>>>> > +test05(Fn f) >>>>>> > +{ >>>>>> > + using namespace __gnu_test; >>>>>> > + X x[] = {{1,500},{2,400},{3,300},{4,200},{5,100}}; >>>>>> > + test_range<X, random_access_iterator_wrapper> rx(x); >>>>>> > + >>>>>> > + auto v = rx | views::pairwise_transform(f); >>>>>> > + VERIFY( ranges::size(v) == 4 ); >>>>>> > + VERIFY( ranges::distance(v.begin(), v.end()) == 4 ); >>>>>> > + VERIFY( ranges::equal(v, (int[]){401,302,203,104}) ); >>>>>> > + VERIFY( ranges::equal(v | views::reverse, >>>>>> (int[]){104,203,302,401}) ); >>>>>> > + using R = decltype(v); >>>>>> > + using It = ranges::iterator_t<R>; >>>>>> > + static_assert(std::same_as<int, decltype(*ranges::begin(v))>); >>>>>> > + static_assert(std::same_as<int, std::iter_value_t<It>>); >>>>>> > + static_assert(sizeof(It) == 2*sizeof(rx.begin()) + FuncSize); >>>>>> > + static_assert(ranges::view<R>); >>>>>> > + static_assert(ranges::sized_range<R>); >>>>>> > + static_assert(!ranges::common_range<R>); >>>>>> > + static_assert(ranges::random_access_range<R>); >>>>>> > + return true; >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05a() >>>>>> > +{ >>>>>> > + auto comb = [](const X& x1, const X& x2) { return x1.i + x2.j; }; >>>>>> > + return test05<sizeof(void*)>(comb); >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05b() >>>>>> > +{ >>>>>> > + auto comb = [](const X& x1, const X& x2) static { return x1.i + >>>>>> x2.j; }; >>>>>> > + return test05<0>(comb); >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05c() >>>>>> > +{ >>>>>> > + int(*comb)(const X&, const X&) = [](const X& x1, const X& x2) { >>>>>> return x1.i + x2.j; }; >>>>>> > + return test05<sizeof(void(*)())>(comb); >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05d() >>>>>> > +{ >>>>>> > + return test05<sizeof(int(X::*)())>(&X::combine); >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05e() >>>>>> > +{ >>>>>> > + struct PickStatic >>>>>> > + { >>>>>> > + static constexpr int >>>>>> > + operator()(const X& x1, const X& x2) >>>>>> > + { return x1.i + x2.j; } >>>>>> > + >>>>>> > + constexpr int >>>>>> > + operator()(int x, int y) const >>>>>> > + { return x + y; }; >>>>>> > + }; >>>>>> > + return test05<0>(PickStatic{}); >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05f() >>>>>> > +{ >>>>>> > + struct PickObject >>>>>> > + { >>>>>> > + constexpr int >>>>>> > + operator()(const X& x1, const X& x2) const >>>>>> > + { return x1.i + x2.j; } >>>>>> > + >>>>>> > + static constexpr int >>>>>> > + operator()(int x, int y) >>>>>> > + { return x + y; }; >>>>>> > + }; >>>>>> > + return test05<sizeof(void*)>(PickObject{}); >>>>>> > +} >>>>>> > + >>>>>> > int >>>>>> > main() >>>>>> > { >>>>>> > @@ -120,4 +211,10 @@ main() >>>>>> > static_assert(test02()); >>>>>> > static_assert(test03()); >>>>>> > test04(); >>>>>> > + static_assert(test05a()); >>>>>> > + static_assert(test05b()); >>>>>> > + static_assert(test05c()); >>>>>> > + static_assert(test05d()); >>>>>> > + static_assert(test05e()); >>>>>> > + static_assert(test05f()); >>>>>> > } >>>>>> > diff --git >>>>>> a/libstdc++-v3/testsuite/std/ranges/adaptors/transform.cc >>>>>> b/libstdc++-v3/testsuite/std/ranges/adaptors/transform.cc >>>>>> > index 1788db1ce8d..c6d6b916730 100644 >>>>>> > --- a/libstdc++-v3/testsuite/std/ranges/adaptors/transform.cc >>>>>> > +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/transform.cc >>>>>> > @@ -28,12 +28,12 @@ using >>>>>> __gnu_test::random_access_iterator_wrapper; >>>>>> > namespace ranges = std::ranges; >>>>>> > namespace views = std::ranges::views; >>>>>> > >>>>>> > +template<typename Fn> >>>>>> > void >>>>>> > -test01() >>>>>> > +test01(Fn f) >>>>>> > { >>>>>> > int x[] = {1,2,3,4,5}; >>>>>> > - auto is_odd = [] (int i) { return i%2==1; }; >>>>>> > - auto v = x | views::transform(is_odd); >>>>>> > + auto v = x | views::transform(f); >>>>>> > VERIFY( ranges::equal(v, (int[]){1,0,1,0,1}) ); >>>>>> > using R = decltype(v); >>>>>> > static_assert(std::same_as<bool, decltype(*ranges::begin(v))>); >>>>>> > @@ -42,30 +42,124 @@ test01() >>>>>> > static_assert(ranges::random_access_range<R>); >>>>>> > } >>>>>> > >>>>>> > +void >>>>>> > +test01a() >>>>>> > +{ >>>>>> > + auto is_odd = [] (int i) { return i%2==1; }; >>>>>> > + test01(is_odd); >>>>>> > +} >>>>>> > + >>>>>> > +void >>>>>> > +test01b() >>>>>> > +{ >>>>>> > +#if __cpp_static_call_operator >= 202207L >>>>>> > + auto is_odd = [] (int i) static { return i%2==1; }; >>>>>> > + test01(is_odd); >>>>>> > +#endif >>>>>> > +} >>>>>> > + >>>>>> > +void >>>>>> > +test01c() >>>>>> > +{ >>>>>> > + bool(*is_odd)(int) = [] (int i) { return i%2==1; }; >>>>>> > + test01(is_odd); >>>>>> > +} >>>>>> > + >>>>>> > struct X >>>>>> > { >>>>>> > int i,j; >>>>>> > + int& first() { return i; } >>>>>> > }; >>>>>> > >>>>>> > +template<size_t FuncSize, typename Fn> >>>>>> > void >>>>>> > -test02() >>>>>> > +test02(Fn f) >>>>>> > { >>>>>> > X x[] = {{1,2},{3,4},{5,6},{7,8},{9,10}}; >>>>>> > test_range<X, random_access_iterator_wrapper> rx(x); >>>>>> > - auto v = rx | views::transform(&X::i); >>>>>> > + auto v = rx | views::transform(f); >>>>>> > VERIFY( ranges::size(v) == 5 ); >>>>>> > VERIFY( ranges::distance(v.begin(), v.end()) == 5 ); >>>>>> > VERIFY( ranges::equal(v, (int[]){1,3,5,7,9}) ); >>>>>> > VERIFY( ranges::equal(v | views::reverse, (int[]){9,7,5,3,1}) ); >>>>>> > using R = decltype(v); >>>>>> > + using It = ranges::iterator_t<R>; >>>>>> > static_assert(std::same_as<int&, decltype(*ranges::begin(v))>); >>>>>> > - static_assert(std::same_as<int, >>>>>> std::iter_value_t<ranges::iterator_t<R>>>); >>>>>> > + static_assert(std::same_as<int, std::iter_value_t<It>>); >>>>>> > + static_assert(sizeof(It) == sizeof(rx.begin()) + FuncSize); >>>>>> > static_assert(ranges::view<R>); >>>>>> > static_assert(ranges::sized_range<R>); >>>>>> > static_assert(!ranges::common_range<R>); >>>>>> > static_assert(ranges::random_access_range<R>); >>>>>> > } >>>>>> > >>>>>> > +void >>>>>> > +test02a() >>>>>> > +{ test02<sizeof(int X::*)>(&X::i); } >>>>>> > + >>>>>> > +void >>>>>> > +test02b() >>>>>> > +{ test02<sizeof(int(X::*)())>(&X::first); } >>>>>> > + >>>>>> > +void >>>>>> > +test02c() >>>>>> > +{ >>>>>> > + auto first = [](X& x) -> int& { return x.i; }; >>>>>> > + test02<sizeof(void*)>(first); >>>>>> > +} >>>>>> > + >>>>>> > +void >>>>>> > +test02d() >>>>>> > +{ >>>>>> > +#if __cpp_static_call_operator >= 202207L >>>>>> > + auto first = [](X& x) static -> int& { return x.i; }; >>>>>> > + test02<0>(first); >>>>>> > +#endif >>>>>> > +} >>>>>> > + >>>>>> > +void >>>>>> > +test02e() >>>>>> > +{ >>>>>> > + int&(*fptr)(X&) = [](X& x) -> int& { return x.i; }; >>>>>> > + test02<sizeof(void(*)())>(fptr); >>>>>> > +} >>>>>> > + >>>>>> > +void >>>>>> > +test02f() >>>>>> > +{ >>>>>> > +#if __cpp_static_call_operator >= 202207L >>>>>> > + struct PickStatic >>>>>> > + { >>>>>> > + static constexpr int& >>>>>> > + operator()(X& x) >>>>>> > + { return x.i; } >>>>>> > + >>>>>> > + constexpr int >>>>>> > + operator()(char*) const >>>>>> > + { return 0; }; >>>>>> > + }; >>>>>> > + test02<0>(PickStatic{}); >>>>>> > +#endif >>>>>> > +} >>>>>> > + >>>>>> > +void >>>>>> > +test02g() >>>>>> > +{ >>>>>> > +#if __cpp_static_call_operator >= 202207L >>>>>> > + struct PickObject >>>>>> > + { >>>>>> > + constexpr int& >>>>>> > + operator()(X& x) const >>>>>> > + { return x.i; } >>>>>> > + >>>>>> > + static constexpr int >>>>>> > + operator()(char*) >>>>>> > + { return 0; }; >>>>>> > + }; >>>>>> > + test02<sizeof(void*)>(PickObject{}); >>>>>> > +#endif >>>>>> > +} >>>>>> > + >>>>>> > void >>>>>> > test03() >>>>>> > { >>>>>> > @@ -230,8 +324,16 @@ test11() >>>>>> > int >>>>>> > main() >>>>>> > { >>>>>> > - test01(); >>>>>> > - test02(); >>>>>> > + test01a(); >>>>>> > + test01b(); >>>>>> > + test01c(); >>>>>> > + test02a(); >>>>>> > + test02b(); >>>>>> > + test02c(); >>>>>> > + test02d(); >>>>>> > + test02e(); >>>>>> > + test02f(); >>>>>> > + test02g(); >>>>>> > test03(); >>>>>> > test04(); >>>>>> > test05(); >>>>>> > diff --git a/libstdc++-v3/testsuite/std/ranges/zip_transform/1.cc >>>>>> b/libstdc++-v3/testsuite/std/ranges/zip_transform/1.cc >>>>>> > index 9a0ad3814e6..d4bd7db26cb 100644 >>>>>> > --- a/libstdc++-v3/testsuite/std/ranges/zip_transform/1.cc >>>>>> > +++ b/libstdc++-v3/testsuite/std/ranges/zip_transform/1.cc >>>>>> > @@ -132,6 +132,97 @@ test04() >>>>>> > static_assert( requires { views::zip_transform(move_only{}, x, >>>>>> x); } ); >>>>>> > } >>>>>> > >>>>>> > +struct X >>>>>> > +{ >>>>>> > + int i; >>>>>> > + constexpr int add(int b) const >>>>>> > + { return i+b; } >>>>>> > +}; >>>>>> > + >>>>>> > +template<size_t ExtraSize, typename Fn> >>>>>> > +constexpr bool >>>>>> > +test05(Fn f) >>>>>> > +{ >>>>>> > + using namespace __gnu_test; >>>>>> > + X x[] = {{1},{2},{3},{4},{5}}; >>>>>> > + int y[] = {500,400,300,200,100}; >>>>>> > + test_range<X, random_access_iterator_wrapper> rx(x); >>>>>> > + test_range<int, random_access_iterator_wrapper> ry(y); >>>>>> > + >>>>>> > + auto v = views::zip_transform(f, rx, ry); >>>>>> > + VERIFY( ranges::size(v) == 5 ); >>>>>> > + VERIFY( ranges::distance(v.begin(), v.end()) == 5 ); >>>>>> > + VERIFY( ranges::equal(v, (int[]){501,402,303,204,105}) ); >>>>>> > + VERIFY( ranges::equal(v | views::reverse, >>>>>> (int[]){105,204,303,402,501}) ); >>>>>> > + using R = decltype(v); >>>>>> > + using It = ranges::iterator_t<R>; >>>>>> > + static_assert(std::same_as<int, decltype(*ranges::begin(v))>); >>>>>> > + static_assert(std::same_as<int, std::iter_value_t<It>>); >>>>>> > + static_assert(sizeof(It) == sizeof(rx.begin()) + >>>>>> sizeof(ry.begin()) + ExtraSize); >>>>>> > + static_assert(ranges::view<R>); >>>>>> > + static_assert(ranges::sized_range<R>); >>>>>> > + static_assert(ranges::common_range<R>); >>>>>> > + static_assert(ranges::random_access_range<R>); >>>>>> > + return true; >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05a() >>>>>> > +{ >>>>>> > + auto add = [](const X& x, int v) { return x.i + v; }; >>>>>> > + return test05<sizeof(void*)>(add); >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05b() >>>>>> > +{ >>>>>> > + auto add = [](const X& x, int v) static { return x.i + v; }; >>>>>> > + return test05<0>(add); >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05c() >>>>>> > +{ >>>>>> > + int(*ptr)(const X&, int) = [](const X& x, int v) { return x.i + >>>>>> v; }; >>>>>> > + return test05<sizeof(void(*)())>(ptr); >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05d() >>>>>> > +{ return test05<sizeof(int(X::*)())>(&X::add); } >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05e() >>>>>> > +{ >>>>>> > + struct PickStatic >>>>>> > + { >>>>>> > + static constexpr int >>>>>> > + operator()(const X& x1, int v) >>>>>> > + { return x1.i + v; } >>>>>> > + >>>>>> > + constexpr int >>>>>> > + operator()(int x, int y) const >>>>>> > + { return x + y; }; >>>>>> > + }; >>>>>> > + return test05<0>(PickStatic{}); >>>>>> > +} >>>>>> > + >>>>>> > +constexpr bool >>>>>> > +test05f() >>>>>> > +{ >>>>>> > + struct PickObject >>>>>> > + { >>>>>> > + constexpr int >>>>>> > + operator()(const X& x1, int v) const >>>>>> > + { return x1.i + v; } >>>>>> > + >>>>>> > + static constexpr int >>>>>> > + operator()(int x, int y) >>>>>> > + { return x + y; }; >>>>>> > + }; >>>>>> > + return test05<sizeof(void*)>(PickObject{}); >>>>>> > +} >>>>>> > + >>>>>> > int >>>>>> > main() >>>>>> > { >>>>>> > @@ -139,4 +230,14 @@ main() >>>>>> > static_assert(test02()); >>>>>> > static_assert(test03()); >>>>>> > test04(); >>>>>> > + static_assert(test01()); >>>>>> > + static_assert(test02()); >>>>>> > + static_assert(test03()); >>>>>> > + test04(); >>>>>> > + static_assert(test05a()); >>>>>> > + static_assert(test05b()); >>>>>> > + static_assert(test05c()); >>>>>> > + static_assert(test05d()); >>>>>> > + static_assert(test05e()); >>>>>> > + static_assert(test05f()); >>>>>> > } >>>>>> > -- >>>>>> > 2.51.0 >>>>>> > >>>>>> > >>>>> >>>>>
