2 files changed, 43 insertions, 4 deletions
diff --git a/src/corelib/global/qendian.h b/src/corelib/global/qendian.h
index c5ff82c10a..34bb015a2f 100644
--- a/src/corelib/global/qendian.h
+++ b/src/corelib/global/qendian.h
@@ -49,6 +49,11 @@
 
 QT_BEGIN_NAMESPACE
 
+#ifdef __has_builtin
+#  define QT_HAS_BUILTIN(x)     __has_builtin(x)
+#else
+#  define QT_HAS_BUILTIN(x)     0
+#endif
 
 /*
  * ENDIAN FUNCTIONS
@@ -71,18 +76,29 @@ template <typename T> inline void qbswap(const T src, uchar *dest)
 
 // Used to implement a type-safe and alignment-safe copy operation
 // If you want to avoid the memcpy, you must write specializations for these functions
-template <typename T> inline void qToUnaligned(const T src, uchar *dest)
+template <typename T> Q_ALWAYS_INLINE void qToUnaligned(const T src, uchar *dest)
 {
     // Using sizeof(T) inside memcpy function produces internal compiler error with
     // MSVC2008/ARM in tst_endian -> use extra indirection to resolve size of T.
     const size_t size = sizeof(T);
-    memcpy(dest, &src, size);
+#if QT_HAS_BUILTIN(__builtin_memcpy)
+    __builtin_memcpy
+#else
+    memcpy
+#endif
+            (dest, &src, size);
 }
-template <typename T> inline T qFromUnaligned(const uchar *src)
+
+template <typename T> Q_ALWAYS_INLINE T qFromUnaligned(const uchar *src)
 {
     T dest;
     const size_t size = sizeof(T);
-    memcpy(&dest, src, size);
+#if QT_HAS_BUILTIN(__builtin_memcpy)
+    __builtin_memcpy
+#else
+    memcpy
+#endif
+            (&dest, src, size);
     return dest;
 }
 
diff --git a/src/corelib/global/qendian.qdoc b/src/corelib/global/qendian.qdoc
index 63d924211f..3b22dcec87 100644
--- a/src/corelib/global/qendian.qdoc
+++ b/src/corelib/global/qendian.qdoc
@@ -34,6 +34,29 @@
 */
 
 /*!
+    \internal
+    \fn T qFromUnaligned(const uchar *ptr)
+    \since 5.5
+
+    Loads a \c{T} from address \a ptr, which may be misaligned.
+
+    Use of this function avoids the undefined behavior that the C++ standard
+    otherwise attributes to unaligned loads.
+*/
+
+/*!
+    \internal
+    \fn void qToUnaligned(T t, uchar *ptr)
+    \since 4.5
+
+    Stores \a t to address \a ptr, which may be misaligned.
+
+    Use of this function avoids the undefined behavior that the C++ standard
+    otherwise attributes to unaligned stores.
+*/
+
+
+/*!
     \fn T qFromBigEndian(const uchar *src)
     \since 4.3
     \relates <QtEndian>