From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Sat, 13 Jul 2024 15:24:30 -0700
Subject: [PATCH 36/37] Fix AlignedCharArrayUnion for C++23

---
 llvm/include/llvm/Support/AlignOf.h | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/llvm/include/llvm/Support/AlignOf.h b/llvm/include/llvm/Support/AlignOf.h
index f586d7f182aab6e56b7fae6ae98a7cd89e63976c..ca98a564733a07a5e16122d31805e970bf76b673 100644
--- a/llvm/include/llvm/Support/AlignOf.h
+++ b/llvm/include/llvm/Support/AlignOf.h
@@ -13,20 +13,16 @@
 #ifndef LLVM_SUPPORT_ALIGNOF_H
 #define LLVM_SUPPORT_ALIGNOF_H
 
-#include <type_traits>
+#include <algorithm>
+#include <cstddef>
 
 namespace llvm {
 
 /// A suitably aligned and sized character array member which can hold elements
 /// of any type.
-///
-/// This template is equivalent to std::aligned_union_t<1, ...>, but we cannot
-/// use it due to a bug in the MSVC x86 compiler:
-/// https://github.com/microsoft/STL/issues/1533
-/// Using `alignas` here works around the bug.
-template <typename T, typename... Ts> struct AlignedCharArrayUnion {
-  using AlignedUnion = std::aligned_union_t<1, T, Ts...>;
-  alignas(alignof(AlignedUnion)) char buffer[sizeof(AlignedUnion)];
+template <typename... Ts> struct AlignedCharArrayUnion {
+  alignas((std::max)({alignof(Ts)...}))
+      std::byte buffer[(std::max)({static_cast<size_t>(1), sizeof(Ts)...})];
 };
 
 } // end namespace llvm