[llvm] [Support] Remove AlignedCharArrayUnion from Expected and ErrorOr, NFCI. (PR #127407)

[Jonas Hahnfeld via llvm-commits]

https://github.com/hahnjo created https://github.com/llvm/llvm-project/pull/127407

They were instantiated with only a single type and union-members themselves. By putting the types directly into a union, they are still left uninitialized by default.

>From 0c829d6fbfbd3e384fb9ad9d08bb583b69d8b08e Mon Sep 17 00:00:00 2001
From: Jonas Hahnfeld <hahnjo at hahnjo.de>
Date: Sun, 16 Feb 2025 17:30:19 +0100
Subject: [PATCH 1/2] Remove unused include

---
 llvm/include/llvm/Support/TrailingObjects.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/llvm/include/llvm/Support/TrailingObjects.h b/llvm/include/llvm/Support/TrailingObjects.h
index 9f7c421a87f4e..07cf08df45a6a 100644
--- a/llvm/include/llvm/Support/TrailingObjects.h
+++ b/llvm/include/llvm/Support/TrailingObjects.h
@@ -46,7 +46,6 @@
 #ifndef LLVM_SUPPORT_TRAILINGOBJECTS_H
 #define LLVM_SUPPORT_TRAILINGOBJECTS_H
 
-#include "llvm/Support/AlignOf.h"
 #include "llvm/Support/Alignment.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/MathExtras.h"

>From 433aa9e1e829a2ab7fb2bd54408a9cedc360a114 Mon Sep 17 00:00:00 2001
From: Jonas Hahnfeld <hahnjo at hahnjo.de>
Date: Sun, 16 Feb 2025 20:04:36 +0100
Subject: [PATCH 2/2] [Support] Remove AlignedCharArrayUnion from Expected and
 ErrorOr, NFCI.

They were instantiated with only a single type and union-members
themselves. By putting the types directly into a union, they are
still left uninitialized by default.
---
 llvm/include/llvm/Support/Error.h   | 5 ++---
 llvm/include/llvm/Support/ErrorOr.h | 5 ++---
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/llvm/include/llvm/Support/Error.h b/llvm/include/llvm/Support/Error.h
index c1b809a09bb80..ddb4f9b7eec87 100644
--- a/llvm/include/llvm/Support/Error.h
+++ b/llvm/include/llvm/Support/Error.h
@@ -16,7 +16,6 @@
 #include "llvm-c/Error.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Config/abi-breaking.h"
-#include "llvm/Support/AlignOf.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -727,8 +726,8 @@ template <class T> class [[nodiscard]] Expected {
   }
 
   union {
-    AlignedCharArrayUnion<storage_type> TStorage;
-    AlignedCharArrayUnion<error_type> ErrorStorage;
+    storage_type TStorage;
+    error_type ErrorStorage;
   };
   bool HasError : 1;
 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
diff --git a/llvm/include/llvm/Support/ErrorOr.h b/llvm/include/llvm/Support/ErrorOr.h
index 97c7abe1f20c5..7f2b0fbce05fd 100644
--- a/llvm/include/llvm/Support/ErrorOr.h
+++ b/llvm/include/llvm/Support/ErrorOr.h
@@ -15,7 +15,6 @@
 #ifndef LLVM_SUPPORT_ERROROR_H
 #define LLVM_SUPPORT_ERROROR_H
 
-#include "llvm/Support/AlignOf.h"
 #include <cassert>
 #include <system_error>
 #include <type_traits>
@@ -252,8 +251,8 @@ class ErrorOr {
   }
 
   union {
-    AlignedCharArrayUnion<storage_type> TStorage;
-    AlignedCharArrayUnion<std::error_code> ErrorStorage;
+    storage_type TStorage;
+    std::error_code ErrorStorage;
   };
   bool HasError : 1;
 };