[libcxx-commits] [libcxx] Lower std::string's alignment requirement from 16 to 8. (PR #68749)

[Louis Dionne via libcxx-commits]

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@@ -1851,7 +1851,14 @@ private:
         _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
         size_type __align_it(size_type __s) _NOEXCEPT
             {return (__s + (__a-1)) & ~(__a-1);}
-    enum {__alignment = 16};
+    enum {
+      __alignment =
+#ifdef _LIBCPP_ABI_STRING_8_BYTE_ALIGNMENT
+      8
+#else
+      16
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ldionne wrote:

Do you know why the library originally used `16`?

https://github.com/llvm/llvm-project/pull/68749