[libcxx-commits] [libcxx] [libcxx] Align allocation to match `__set_long_cap` and `__get_long_cap` (PR #90292)

[Vitaly Buka via libcxx-commits]

================
@@ -1959,10 +1960,10 @@ private:
     if (__s < __min_cap) {
       return static_cast<size_type>(__min_cap) - 1;
     }
-    const size_type __boundary = sizeof(value_type) < __alignment ? __alignment / sizeof(value_type) : 1;
+    const size_type __boundary = sizeof(value_type) < __alignment ? __alignment / sizeof(value_type) : __endian_factor;
     size_type __guess          = __align_it<__boundary>(__s + 1) - 1;
     if (__guess == __min_cap)
-      ++__guess;
+      __guess += 2;
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vitalybuka wrote:

works with ASSERT, and likely will work with asan
Should `__guess += 2` be replaced with  `__guess += __endian_factor` if we want to keep  __endian_factor alignment?

https://github.com/llvm/llvm-project/pull/90292