This implements P1004R2 ("Making std::vector constexpr") for C++20.
For now, debug mode vectors are not supported in constant expressions.
To make that work we might need to disable all attaching/detaching of
safe iterators. That can be fixed later.
Co-authored-by: Josh Marshall <joshua.r.marshall.1991@gmail.com>
libstdc++-v3/ChangeLog:
* include/bits/alloc_traits.h (_Destroy): Make constexpr for
C++20 mode.
* include/bits/allocator.h (__shrink_to_fit::_S_do_it):
Likewise.
* include/bits/stl_algobase.h (__fill_a1): Declare _Bit_iterator
overload constexpr for C++20.
* include/bits/stl_bvector.h (_Bit_type, _S_word_bit): Move out
of inline namespace.
(_Bit_reference, _Bit_iterator_base, _Bit_iterator)
(_Bit_const_iterator, _Bvector_impl_data, _Bvector_base)
(vector<bool, A>>): Add constexpr to every member function.
(_Bvector_base::_M_allocate): Initialize storage during constant
evaluation.
(vector<bool, A>::_M_initialize_value): Use __fill_bvector_n
instead of memset.
(__fill_bvector_n): New helper function to replace memset during
constant evaluation.
* include/bits/stl_uninitialized.h (__uninitialized_copy<false>):
Move logic to ...
(__do_uninit_copy): New function.
(__uninitialized_fill<false>): Move logic to ...
(__do_uninit_fill): New function.
(__uninitialized_fill_n<false>): Move logic to ...
(__do_uninit_fill_n): New function.
(__uninitialized_copy_a): Add constexpr. Use __do_uninit_copy.
(__uninitialized_move_a, __uninitialized_move_if_noexcept_a):
Add constexpr.
(__uninitialized_fill_a): Add constexpr. Use __do_uninit_fill.
(__uninitialized_fill_n_a): Add constexpr. Use
__do_uninit_fill_n.
(__uninitialized_default_n, __uninitialized_default_n_a)
(__relocate_a_1, __relocate_a): Add constexpr.
* include/bits/stl_vector.h (_Vector_impl_data, _Vector_impl)
(_Vector_base, vector): Add constexpr to every member function.
(_Vector_impl::_S_adjust): Disable ASan annotation during
constant evaluation.
(_Vector_base::_S_use_relocate): Disable bitwise-relocation
during constant evaluation.
(vector::_Temporary_value): Use a union for storage.
* include/bits/vector.tcc (vector, vector<bool>): Add constexpr
to every member function.
* include/std/vector (erase_if, erase): Add constexpr.
* testsuite/23_containers/headers/vector/synopsis.cc: Add
constexpr for C++20 mode.
* testsuite/23_containers/vector/bool/cmp_c++20.cc: Change to
compile-only test using constant expressions.
* testsuite/23_containers/vector/bool/capacity/29134.cc: Adjust
namespace for _S_word_bit.
* testsuite/23_containers/vector/bool/modifiers/insert/31370.cc:
Likewise.
* testsuite/23_containers/vector/cmp_c++20.cc: Likewise.
* testsuite/23_containers/vector/cons/89164.cc: Adjust errors
for C++20 and move C++17 test to ...
* testsuite/23_containers/vector/cons/89164_c++17.cc: ... here.
* testsuite/23_containers/vector/bool/capacity/constexpr.cc: New test.
* testsuite/23_containers/vector/bool/cons/constexpr.cc: New test.
* testsuite/23_containers/vector/bool/element_access/constexpr.cc: New test.
* testsuite/23_containers/vector/bool/modifiers/assign/constexpr.cc: New test.
* testsuite/23_containers/vector/bool/modifiers/constexpr.cc: New test.
* testsuite/23_containers/vector/bool/modifiers/swap/constexpr.cc: New test.
* testsuite/23_containers/vector/capacity/constexpr.cc: New test.
* testsuite/23_containers/vector/cons/constexpr.cc: New test.
* testsuite/23_containers/vector/data_access/constexpr.cc: New test.
* testsuite/23_containers/vector/element_access/constexpr.cc: New test.
* testsuite/23_containers/vector/modifiers/assign/constexpr.cc: New test.
* testsuite/23_containers/vector/modifiers/constexpr.cc: New test.
* testsuite/23_containers/vector/modifiers/swap/constexpr.cc: New test.
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