MSVC: add support for 64-bit POPCNT on 32-bit machines

It's just adding the count of each half. Change-Id: I9868946ceaf74002bde1fffd154b29908319007f Reviewed-by: Samuel Gaist <[email protected]> Reviewed-by: Olivier Goffart (Woboq GmbH) <[email protected]>
Tanvir-Aunjum-Sunny · Aug 16, 2018 · 04bbf53 · 04bbf53
1 parent 242ea38
commit 04bbf53
Showing 1 changed file with 6 additions and 3 deletions.
diff --git a/src/corelib/tools/qalgorithms.h b/src/corelib/tools/qalgorithms.h
@@ -651,6 +651,7 @@ Q_ALWAYS_INLINE uint qt_builtin_clzs(quint16 v) Q_DECL_NOTHROW
 // So it's an acceptable compromise.
 #if defined(__AVX__) || defined(__SSE4_2__) || defined(__POPCNT__)
 #define QALGORITHMS_USE_BUILTIN_POPCOUNT
+#define QALGORITHMS_USE_BUILTIN_POPCOUNTLL
 Q_ALWAYS_INLINE uint qt_builtin_popcount(quint32 v) Q_DECL_NOTHROW
 {
     return __popcnt(v);
@@ -663,13 +664,15 @@ Q_ALWAYS_INLINE uint qt_builtin_popcount(quint16 v) Q_DECL_NOTHROW
 {
     return __popcnt16(v);
 }
-#if Q_PROCESSOR_WORDSIZE == 8
-#define QALGORITHMS_USE_BUILTIN_POPCOUNTLL
 Q_ALWAYS_INLINE uint qt_builtin_popcountll(quint64 v) Q_DECL_NOTHROW
 {
+#if Q_PROCESSOR_WORDSIZE == 8
     return __popcnt64(v);
-}
+#else
+    return __popcnt(quint32(v)) + __popcnt(quint32(v >> 32));
 #endif // MSVC 64bit
+}
+
 #endif // __AVX__ || __SSE4_2__ || __POPCNT__
 
 #endif // MSVC