[libcxx-commits] [libcxx] [libcxx] adds a size-based representation for `vector`'s unstable ABI (PR #155330)

[Louis Dionne via libcxx-commits]

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@@ -1051,11 +1048,12 @@ _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void
 vector<_Tp, _Allocator>::__assign_with_size(_Iterator __first, _Sentinel __last, difference_type __n) {
   size_type __new_size = static_cast<size_type>(__n);
   if (__new_size <= capacity()) {
-    if (__new_size > size()) {
-      auto __mid = std::__copy_n<_AlgPolicy>(std::move(__first), size(), this->__begin_).first;
-      __construct_at_end(std::move(__mid), std::move(__last), __new_size - size());
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ldionne wrote:

We could simplify the diff slightly by refactoring this code to call `size()` only once before this PR. I'm not requesting it, but if you're up for it, I think it would be a clean, small and uncontroversial refactoring to the current code.

https://github.com/llvm/llvm-project/pull/155330