From 86eb41f1cb016916d0813da851ec39a244ff6d8f Mon Sep 17 00:00:00 2001
From: Joel Holdsworth <joel.holdsworth@vcatechnology.com>
Date: Thu, 7 Nov 2019 14:34:06 +0000
Subject: SparseRef: Fixed alignment warning on ARM GCC

---
 Eigen/src/Core/util/Meta.h       | 10 ++++++++++
 Eigen/src/SparseCore/SparseRef.h | 14 +++++++-------
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/Eigen/src/Core/util/Meta.h b/Eigen/src/Core/util/Meta.h
index fe9550d71..2153f2c0d 100755
--- a/Eigen/src/Core/util/Meta.h
+++ b/Eigen/src/Core/util/Meta.h
@@ -612,6 +612,16 @@ template<typename T, typename U> struct scalar_product_traits
 // typedef typename scalar_product_traits<typename remove_all<ArgType0>::type, typename remove_all<ArgType1>::type>::ReturnType type;
 // };
 
+/** \internal Obtains a POD type suitable to use as storage for an object of a size
+  * of at most Len bytes, aligned as specified by \c Align.
+  */
+template<unsigned Len, unsigned Align>
+struct aligned_storage {
+  struct type {
+    EIGEN_ALIGN_TO_BOUNDARY(Align) unsigned char data[Len];
+  };
+};
+
 } // end namespace internal
 
 namespace numext {
diff --git a/Eigen/src/SparseCore/SparseRef.h b/Eigen/src/SparseCore/SparseRef.h
index d91f38f97..748f87d62 100644
--- a/Eigen/src/SparseCore/SparseRef.h
+++ b/Eigen/src/SparseCore/SparseRef.h
@@ -201,7 +201,7 @@ class Ref<const SparseMatrix<MatScalar,MatOptions,MatIndex>, Options, StrideType
 
     ~Ref() {
       if(m_hasCopy) {
-        TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(m_object_bytes);
+        TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(&m_storage);
         obj->~TPlainObjectType();
       }
     }
@@ -213,7 +213,7 @@ class Ref<const SparseMatrix<MatScalar,MatOptions,MatIndex>, Options, StrideType
     {
       if((Options & int(StandardCompressedFormat)) && (!expr.isCompressed()))
       {
-        TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(m_object_bytes);
+        TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(&m_storage);
         ::new (obj) TPlainObjectType(expr);
         m_hasCopy = true;
         Base::construct(*obj);
@@ -227,14 +227,14 @@ class Ref<const SparseMatrix<MatScalar,MatOptions,MatIndex>, Options, StrideType
     template<typename Expression>
     void construct(const Expression& expr, internal::false_type)
     {
-      TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(m_object_bytes);
+      TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(&m_storage);
       ::new (obj) TPlainObjectType(expr);
       m_hasCopy = true;
       Base::construct(*obj);
     }
 
   protected:
-    char m_object_bytes[sizeof(TPlainObjectType)];
+    typename internal::aligned_storage<sizeof(TPlainObjectType), EIGEN_ALIGNOF(TPlainObjectType)>::type m_storage;
     bool m_hasCopy;
 };
 
@@ -319,7 +319,7 @@ class Ref<const SparseVector<MatScalar,MatOptions,MatIndex>, Options, StrideType
 
     ~Ref() {
       if(m_hasCopy) {
-        TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(m_object_bytes);
+        TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(&m_storage);
         obj->~TPlainObjectType();
       }
     }
@@ -335,14 +335,14 @@ class Ref<const SparseVector<MatScalar,MatOptions,MatIndex>, Options, StrideType
     template<typename Expression>
     void construct(const Expression& expr, internal::false_type)
     {
-      TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(m_object_bytes);
+      TPlainObjectType* obj = reinterpret_cast<TPlainObjectType*>(&m_storage);
       ::new (obj) TPlainObjectType(expr);
       m_hasCopy = true;
       Base::construct(*obj);
     }
 
   protected:
-    char m_object_bytes[sizeof(TPlainObjectType)];
+    typename internal::aligned_storage<sizeof(TPlainObjectType), EIGEN_ALIGNOF(TPlainObjectType)>::type m_storage;
     bool m_hasCopy;
 };
 
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