From 88eda007a3b5046999dd0b287634765efcd8934d Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Wed, 6 Jun 2018 20:42:32 +0000
Subject: Revert "qsimd: remove support for systems without 64-bit atomics"

This reverts commit 6e1190053d28877b2e90375056735429525e2ee7.
We had to bring back qatomic_msvc.h for MSVC 2015, which does
not provide 64-bit atomics on 32-bit platforms.

Task-number: QTBUG-68719
Change-Id: Iea902cf0b01191717e0a640944771fcede7b5ff8
Reviewed-by: Liang Qi <liang.qi@qt.io>
---
 src/corelib/tools/qsimd.cpp |  7 +++++++
 src/corelib/tools/qsimd_p.h | 17 ++++++++++-------
 2 files changed, 17 insertions(+), 7 deletions(-)

(limited to 'src/corelib')

diff --git a/src/corelib/tools/qsimd.cpp b/src/corelib/tools/qsimd.cpp
index fd9c6a7079..b08e2aa611 100644
--- a/src/corelib/tools/qsimd.cpp
+++ b/src/corelib/tools/qsimd.cpp
@@ -522,7 +522,11 @@ static const int features_count = (sizeof features_indices) / (sizeof features_i
 // record what CPU features were enabled by default in this Qt build
 static const quint64 minFeature = qCompilerCpuFeatures;
 
+#ifdef Q_ATOMIC_INT64_IS_SUPPORTED
 Q_CORE_EXPORT QBasicAtomicInteger<quint64> qt_cpu_features[1] = { Q_BASIC_ATOMIC_INITIALIZER(0) };
+#else
+Q_CORE_EXPORT QBasicAtomicInteger<unsigned> qt_cpu_features[2] = { Q_BASIC_ATOMIC_INITIALIZER(0), Q_BASIC_ATOMIC_INITIALIZER(0) };
+#endif
 
 void qDetectCpuFeatures()
 {
@@ -555,6 +559,9 @@ void qDetectCpuFeatures()
     }
 
     qt_cpu_features[0].store(f | quint32(QSimdInitialized));
+#ifndef Q_ATOMIC_INT64_IS_SUPPORTED
+    qt_cpu_features[1].store(f >> 32);
+#endif
 }
 
 void qDumpCPUFeatures()
diff --git a/src/corelib/tools/qsimd_p.h b/src/corelib/tools/qsimd_p.h
index 1b7ed57fa8..1bc7dd06b1 100644
--- a/src/corelib/tools/qsimd_p.h
+++ b/src/corelib/tools/qsimd_p.h
@@ -297,26 +297,29 @@ static const quint64 qCompilerCpuFeatures = 0
         ;
 #endif
 
-#ifdef QT_BOOTSTRAPPED
-static inline quint64 qCpuFeatures()
-{
-    return QSimdInitialized;
-}
-#else
+#ifdef Q_ATOMIC_INT64_IS_SUPPORTED
 extern Q_CORE_EXPORT QBasicAtomicInteger<quint64> qt_cpu_features[1];
+#else
+extern Q_CORE_EXPORT QBasicAtomicInteger<unsigned> qt_cpu_features[2];
+#endif
 Q_CORE_EXPORT void qDetectCpuFeatures();
 
 static inline quint64 qCpuFeatures()
 {
     quint64 features = qt_cpu_features[0].load();
+#ifndef Q_ATOMIC_INT64_IS_SUPPORTED
+    features |= quint64(qt_cpu_features[1].load()) << 32;
+#endif
     if (Q_UNLIKELY(features == 0)) {
         qDetectCpuFeatures();
         features = qt_cpu_features[0].load();
+#ifndef Q_ATOMIC_INT64_IS_SUPPORTED
+        features |= quint64(qt_cpu_features[1].load()) << 32;
+#endif
         Q_ASSUME(features != 0);
     }
     return features;
 }
-#endif
 
 #define qCpuHasFeature(feature)     ((qCompilerCpuFeatures & (Q_UINT64_C(1) << CpuFeature ## feature)) \
                                      || (qCpuFeatures() & (Q_UINT64_C(1) << CpuFeature ## feature)))
-- 
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