Add special thread pool for Qt Gui

To avoid gui slowdowns due to global pool being blocked.

Fixes: QTBUG-109511
Pick-to: 6.5 6.4 6.2
Change-Id: I4e8d91e8fb0bd2e395072a082e992a3c5d3464ad
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 4 insertions, 3 deletions

diff --git a/src/gui/painting/qimagescale_sse4.cpp b/src/gui/painting/qimagescale_sse4.cpp
index f55290b46c..982e533a32 100644
--- a/src/gui/painting/qimagescale_sse4.cpp
+++ b/src/gui/painting/qimagescale_sse4.cpp
@@ -7,8 +7,9 @@
 #include <private/qsimd_p.h>
 
 #if QT_CONFIG(thread) && !defined(Q_OS_WASM)
-#include "qsemaphore.h"
-#include "qthreadpool.h"
+#include <qsemaphore.h>
+#include <qthreadpool.h>
+#include <private/qthreadpool_p.h>
 #endif
 
 #if defined(QT_COMPILER_SUPPORTS_SSE4_1)
@@ -23,7 +24,7 @@ static inline void multithread_pixels_function(QImageScaleInfo *isi, int dh, con
 #if QT_CONFIG(thread) && !defined(Q_OS_WASM)
     int segments = (qsizetype(isi->sh) * isi->sw) / (1<<16);
     segments = std::min(segments, dh);
-    QThreadPool *threadPool = QThreadPool::globalInstance();
+    QThreadPool *threadPool = QThreadPoolPrivate::qtGuiInstance();
     if (segments > 1 && threadPool && !threadPool->contains(QThread::currentThread())) {
         QSemaphore semaphore;
         int y = 0;