1 files changed, 34 insertions, 3 deletions
diff --git a/src/gui/painting/qrgb.h b/src/gui/painting/qrgb.h
index f7f2185bef..05b3a76bce 100644
--- a/src/gui/painting/qrgb.h
+++ b/src/gui/painting/qrgb.h
@@ -36,6 +36,11 @@
 
 #include <QtCore/qglobal.h>
 #include <QtCore/qprocessordetection.h>
+#if defined(__SSE4_1__)
+#include <smmintrin.h>
+#elif defined(__SSE2__)
+#include <emmintrin.h>
+#endif
 
 QT_BEGIN_NAMESPACE
 
@@ -87,19 +92,45 @@ inline Q_DECL_RELAXED_CONSTEXPR QRgb qPremultiply(QRgb x)
 
 Q_GUI_EXPORT extern const uint qt_inv_premul_factor[];
 
+#if defined(__SSE2__)
+inline QRgb qUnpremultiply(QRgb p)
+{
+    const uint alpha = qAlpha(p);
+    if (alpha == 255 || alpha == 0)
+        return p;
+    const uint invAlpha = qt_inv_premul_factor[alpha];
+    const __m128i via = _mm_set1_epi32(invAlpha);
+    const __m128i vr = _mm_set1_epi32(0x8000);
+#ifdef __SSE4_1__
+    __m128i vl = _mm_cvtepu8_epi32(_mm_cvtsi32_si128(p));
+    vl = _mm_mullo_epi32(vl, via);
+#else
+    __m128i vl = _mm_unpacklo_epi8(_mm_cvtsi32_si128(p), _mm_setzero_si128());
+    vl = _mm_unpacklo_epi16(vl, vl);
+    __m128i vll = _mm_mullo_epi16(vl, via);
+    __m128i vlh = _mm_mulhi_epu16(vl, via);
+    vl = _mm_add_epi32(vll, _mm_slli_epi32(vlh, 16));
+#endif
+    vl = _mm_add_epi32(vl, vr);
+    vl = _mm_srli_epi32(vl, 16);
+    vl = _mm_packs_epi32(vl, _mm_setzero_si128());
+    vl = _mm_insert_epi16(vl, alpha, 3);
+    vl = _mm_packus_epi16(vl, _mm_setzero_si128());
+    return _mm_cvtsi128_si32(vl);
+}
+#else
 inline QRgb qUnpremultiply(QRgb p)
 {
     const uint alpha = qAlpha(p);
     // Alpha 255 and 0 are the two most common values, which makes them beneficial to short-cut.
-    if (alpha == 255)
+    if (alpha == 255 || alpha == 0)
         return p;
-    if (alpha == 0)
-        return 0;
     // (p*(0x00ff00ff/alpha)) >> 16 == (p*255)/alpha for all p and alpha <= 256.
     const uint invAlpha = qt_inv_premul_factor[alpha];
     // We add 0x8000 to get even rounding. The rounding also ensures that qPremultiply(qUnpremultiply(p)) == p for all p.
     return qRgba((qRed(p)*invAlpha + 0x8000)>>16, (qGreen(p)*invAlpha + 0x8000)>>16, (qBlue(p)*invAlpha + 0x8000)>>16, alpha);
 }
+#endif
 
 QT_END_NAMESPACE