From c54fb03446f0b4c6f6492d0bfe459033ea480fe1 Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Tue, 14 Dec 2021 16:40:19 -0300
Subject: QGlobalStatic: don't use a std::aligned_union if we can be a union

Simplifies further the code with C++11 unrestricted unions.

Pick-to: 6.3
Task-number: QTBUG-99122
Change-Id: Ib42b3adc93bf4d43bd55fffd16c0b6677441bf55
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
---
 src/corelib/global/qglobalstatic.h | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

(limited to 'src/corelib/global/qglobalstatic.h')

diff --git a/src/corelib/global/qglobalstatic.h b/src/corelib/global/qglobalstatic.h
index 01e06e5234..cf96e5ae8e 100644
--- a/src/corelib/global/qglobalstatic.h
+++ b/src/corelib/global/qglobalstatic.h
@@ -57,15 +57,17 @@ enum GuardValues {
     Initializing = 1
 };
 
-template <typename QGS> struct Holder
+template <typename QGS> union Holder
 {
     using Type = typename QGS::QGS_Type;
     using PlainType = std::remove_cv_t<Type>;
 
     static constexpr bool ConstructionIsNoexcept = noexcept(QGS::innerFunction(nullptr));
-    std::aligned_union_t<1, PlainType> storage;
     static inline QBasicAtomicInteger<qint8> guard = { QtGlobalStatic::Uninitialized };
 
+    // union's sole member
+    PlainType storage;
+
     Holder() noexcept(ConstructionIsNoexcept)
     {
         QGS::innerFunction(pointer());
@@ -81,7 +83,7 @@ template <typename QGS> struct Holder
 
     PlainType *pointer() noexcept
     {
-        return reinterpret_cast<PlainType *>(&storage);
+        return &storage;
     }
 
     Q_DISABLE_COPY_MOVE(Holder)
-- 
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