Intel CPUs have had this since 2013 (Ivy Bridge), but some older
Bulldozer AMD CPUs appear to be missing it. This creates a mismatch
between when the __haswell__ macro gets declared in qsimd_p.h and the
runtime check using the CpuArchHaswell value. That in turn creates a
condition where qInitDrawhelperFunctions() in qdrawhelper.cpp leaves the
memfill pointers set to null.
#elif defined(__SSE2__)
# ifndef __haswell__
qt_memfill32 = qt_memfill32_sse2;
qt_memfill64 = qt_memfill64_sse2;
# endif
...
#if defined(QT_COMPILER_SUPPORTS_AVX2)
if (qCpuHasFeature(ArchHaswell)) {
qt_memfill32 = qt_memfill32_avx2;
qt_memfill64 = qt_memfill64_avx2;
It does this so the qt_memfillXX_sse2 functions don't have to be defined
anywhere, so the QtGui build won't carry unnecessary dead code.
This is old code (from Qt 4.x) and several improvements I've made for
QtCore are not applied yet. My work for qSimdDispatcher[1] isn't
complete: it might have avoided this problem here, but it would also
have required major work for the draw helpers to work in the first
place.
[1] https://codereview.qt-project.org/c/qt/qtbase/+/537384
Pick-to: 6.7 6.5 6.2
Fixes: QTBUG-129193
Change-Id: Ia427a9e502b0fb46b2bdfffda8e2131b7091c9e9
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
(cherry picked from commit 54c24313fe1e4ed58b3260189cb623a7c852ab1d)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
ea5bff8feb