Revert "Remove separate SSE4 unpremultiply function"

Could causedSSE4 instructions to be used on non SSE4 machines
in cases when qUnpremultiplywas not inlined.

This reverts commit 964ccc58534aac436529007000d1c38d76c88834.

Change-Id: Ic676ade8f75129e8d37c4d96cbfb2bdb5b794919
Task-number: QTBUG-45741
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/auto/gui/painting/qcolor/tst_qcolor.cpp b/tests/auto/gui/painting/qcolor/tst_qcolor.cpp
index c34b1639cc..4fafbf9827 100644
--- a/tests/auto/gui/painting/qcolor/tst_qcolor.cpp
+++ b/tests/auto/gui/painting/qcolor/tst_qcolor.cpp
@@ -38,6 +38,7 @@
 
 #include <qcolor.h>
 #include <qdebug.h>
+#include <private/qdrawingprimitive_sse2_p.h>
 
 class tst_QColor : public QObject
 {
@@ -103,6 +104,7 @@ private slots:
     void achromaticHslHue();
 
     void premultiply();
+    void unpremultiply_sse4();
 
 #ifdef Q_DEAD_CODE_FROM_QT4_X11
     void setallowX11ColorNames();
@@ -1445,5 +1447,22 @@ void tst_QColor::premultiply()
     }
 }
 
+void tst_QColor::unpremultiply_sse4()
+{
+    // Tests that qUnpremultiply_sse4 returns the same as qUnpremultiply.
+#if QT_COMPILER_SUPPORTS_HERE(SSE4_1)
+    if (qCpuHasFeature(SSE4_1)) {
+        for (uint a = 0; a < 256; a++) {
+            for (uint c = 0; c <= a; c++) {
+                QRgb p = qRgba(c, a-c, c, a);
+                QCOMPARE(qUnpremultiply(p), qUnpremultiply_sse4(p));
+            }
+        }
+        return;
+    }
+#endif
+    QSKIP("SSE4 not supported on this CPU.");
+}
+
 QTEST_MAIN(tst_QColor)
 #include "tst_qcolor.moc"