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Optimize and fix basic_string move assignment operator. Reviewed as https://reviews.llvm.org/D68623. Thanks to mvels for the patch.

This commit is contained in:
marshall 2019-11-27 07:13:00 -08:00
parent f59614d906
commit 703c26f03b
1 changed files with 14 additions and 4 deletions
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18
libcxx/include/string
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@ -2289,10 +2289,20 @@ basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, tr
_NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value) _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
#endif #endif
{ {
__clear_and_shrink(); if (__is_long()) {
__r_.first() = __str.__r_.first(); __alloc_traits::deallocate(__alloc(), __get_long_pointer(),
__move_assign_alloc(__str); __get_long_cap());
__str.__zero(); #if _LIBCPP_STD_VER <= 14
if (!is_nothrow_move_assignable<allocator_type>::value) {
__set_short_size(0);
traits_type::assign(__get_short_pointer()[0], value_type());
}
#endif
}
__move_assign_alloc(__str);
__r_.first() = __str.__r_.first();
__str.__set_short_size(0);
traits_type::assign(__str.__get_short_pointer()[0], value_type());
} }
template <class _CharT, class _Traits, class _Allocator> template <class _CharT, class _Traits, class _Allocator>