From eb9b2c8b7b56211ef3f125e17ecdc9139ef92368 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Mon, 26 Jun 2023 11:00:56 +0200
Subject: [PATCH 26/30] QRecyclePool: fix potential UB

Return the pointer returned by placement new, not the pointer used as
input to placement new. There is a subtle difference and this grey
zone of the C++ standard is best avoided (keyword: std::launder()).

Pick-to: 6.6 6.5 6.2 5.15
Change-Id: I27c159cdb29a5837120f3d44aa6c95da040fd1a2
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
(cherry picked from commit 7381110745572478ffa3c68000574bc4ccb2396c)
---
 src/qml/qml/ftw/qrecyclepool_p.h | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/qml/qml/ftw/qrecyclepool_p.h b/src/qml/qml/ftw/qrecyclepool_p.h
index 39f4f88512..c963e1878e 100644
--- a/src/qml/qml/ftw/qrecyclepool_p.h
+++ b/src/qml/qml/ftw/qrecyclepool_p.h
@@ -130,8 +130,7 @@ template<typename T, int Step>
 T *QRecyclePool<T, Step>::New()
 {
     T *rv = d->allocate();
-    new (rv) T;
-    return rv;
+    return new (rv) T;
 }
 
 template<typename T, int Step>
@@ -139,8 +138,7 @@ template<typename T1>
 T *QRecyclePool<T, Step>::New(const T1 &a)
 {
     T *rv = d->allocate();
-    new (rv) T(a);
-    return rv;
+    return new (rv) T(a);
 }
 
 template<typename T, int Step>
@@ -148,8 +146,7 @@ template<typename T1>
 T *QRecyclePool<T, Step>::New(T1 &a)
 {
     T *rv = d->allocate();
-    new (rv) T(a);
-    return rv;
+    return new (rv) T(a);
 }
 
 template<typename T, int Step>
-- 
2.44.0