[libcxx-commits] [libcxx] [libc++] Replace `__compressed_pair` with `[[no_unique_address]]` (PR #76756)

[Louis Dionne via libcxx-commits]

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@@ -293,34 +293,19 @@ struct __shared_ptr_emplace : __shared_weak_count {
 
   // This class implements the control block for non-array shared pointers created
   // through `std::allocate_shared` and `std::make_shared`.
-  //
-  // In previous versions of the library, we used a compressed pair to store
-  // both the _Alloc and the _Tp. This implies using EBO, which is incompatible
-  // with Allocator construction for _Tp. To allow implementing P0674 in C++20,
-  // we now use a properly aligned char buffer while making sure that we maintain
-  // the same layout that we had when we used a compressed pair.
-  using _CompressedPair = __compressed_pair<_Alloc, _Tp>;
-  struct _ALIGNAS_TYPE(_CompressedPair) _Storage {
-    char __blob_[sizeof(_CompressedPair)];
+  struct _Storage {
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ldionne wrote:

Maybe add a `TODO` saying that we can refactor this further now that this is so much simplified? Or create an issue.

https://github.com/llvm/llvm-project/pull/76756