From 8b6d1c0467b2dfa14cb2d2dec7637bf95c78364b Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk@google.com>
Date: Thu, 27 Feb 2020 14:55:13 -0800
Subject: [PATCH] [ADT] Use alignas + sizeof for inline storage, NFC

AlignedCharArrayUnion is really only needed to handle the "union" case
when we need memory of suitable size and alignment for multiple types.
SmallVector only needs storage for one type, so use that directly.
---
 clang/include/clang/AST/APValue.h      |  3 ++-
 llvm/include/llvm/ADT/SmallVector.h    | 10 +++++-----
 llvm/include/llvm/ADT/iterator_range.h |  1 -
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/clang/include/clang/AST/APValue.h b/clang/include/clang/AST/APValue.h
index ac8ed08..5eb1f68 100644
--- a/clang/include/clang/AST/APValue.h
+++ b/clang/include/clang/AST/APValue.h
@@ -17,9 +17,10 @@
 #include "llvm/ADT/APFixedPoint.h"
 #include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/APSInt.h"
+#include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/PointerUnion.h"
-#include "llvm/ADT/FoldingSet.h"
+#include "llvm/Support/AlignOf.h"
 
 namespace clang {
   class AddrLabelExpr;
diff --git a/llvm/include/llvm/ADT/SmallVector.h b/llvm/include/llvm/ADT/SmallVector.h
index c3c6a36..dd5cd95 100644
--- a/llvm/include/llvm/ADT/SmallVector.h
+++ b/llvm/include/llvm/ADT/SmallVector.h
@@ -14,7 +14,6 @@
 #define LLVM_ADT_SMALLVECTOR_H
 
 #include "llvm/ADT/iterator_range.h"
-#include "llvm/Support/AlignOf.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
@@ -97,8 +96,9 @@ using SmallVectorSizeType =
 
 /// Figure out the offset of the first element.
 template <class T, typename = void> struct SmallVectorAlignmentAndSize {
-  AlignedCharArrayUnion<SmallVectorBase<SmallVectorSizeType<T>>> Base;
-  AlignedCharArrayUnion<T> FirstEl;
+  alignas(SmallVectorBase<SmallVectorSizeType<T>>) char Base[sizeof(
+      SmallVectorBase<SmallVectorSizeType<T>>)];
+  alignas(T) char FirstEl[sizeof(T)];
 };
 
 /// This is the part of SmallVectorTemplateBase which does not depend on whether
@@ -870,13 +870,13 @@ SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
 /// to avoid allocating unnecessary storage.
 template <typename T, unsigned N>
 struct SmallVectorStorage {
-  AlignedCharArrayUnion<T> InlineElts[N];
+  alignas(T) char InlineElts[N * sizeof(T)];
 };
 
 /// We need the storage to be properly aligned even for small-size of 0 so that
 /// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is
 /// well-defined.
-template <typename T> struct alignas(alignof(T)) SmallVectorStorage<T, 0> {};
+template <typename T> struct alignas(T) SmallVectorStorage<T, 0> {};
 
 /// This is a 'vector' (really, a variable-sized array), optimized
 /// for the case when the array is small.  It contains some number of elements
diff --git a/llvm/include/llvm/ADT/iterator_range.h b/llvm/include/llvm/ADT/iterator_range.h
index f038f6b..a9b46a3 100644
--- a/llvm/include/llvm/ADT/iterator_range.h
+++ b/llvm/include/llvm/ADT/iterator_range.h
@@ -18,7 +18,6 @@
 #ifndef LLVM_ADT_ITERATOR_RANGE_H
 #define LLVM_ADT_ITERATOR_RANGE_H
 
-#include <iterator>
 #include <utility>
 
 namespace llvm {
-- 
2.7.4