[libcxx-commits] [libcxx] 703c26f - Optimize and fix basic_string move assignment operator. Reviewed as https://reviews.llvm.org/D68623. Thanks to mvels for the patch.
via libcxx-commits
libcxx-commits at lists.llvm.org
Wed Nov 27 07:13:43 PST 2019
Author: marshall
Date: 2019-11-27T07:13:32-08:00
New Revision: 703c26f03be74daf6e483380e6b23029a3851081
URL: https://github.com/llvm/llvm-project/commit/703c26f03be74daf6e483380e6b23029a3851081
DIFF: https://github.com/llvm/llvm-project/commit/703c26f03be74daf6e483380e6b23029a3851081.diff
LOG: Optimize and fix basic_string move assignment operator. Reviewed as https://reviews.llvm.org/D68623. Thanks to mvels for the patch.
Added:
Modified:
libcxx/include/string
Removed:
################################################################################
diff --git a/libcxx/include/string b/libcxx/include/string
index c16dbedc51c0..4e0b21135a7e 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -2289,10 +2289,20 @@ basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, tr
_NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
#endif
{
- __clear_and_shrink();
- __r_.first() = __str.__r_.first();
- __move_assign_alloc(__str);
- __str.__zero();
+ if (__is_long()) {
+ __alloc_traits::deallocate(__alloc(), __get_long_pointer(),
+ __get_long_cap());
+#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>
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