1 files changed, 5 insertions, 1 deletions
diff --git a/src/corelib/global/qnumeric_p.h b/src/corelib/global/qnumeric_p.h
index 7418579fe0..7a03e32699 100644
--- a/src/corelib/global/qnumeric_p.h
+++ b/src/corelib/global/qnumeric_p.h
@@ -202,7 +202,7 @@ namespace {
     This function works for v containing infinities, but not NaN. It's the
     caller's responsibility to exclude that possibility before calling it.
 */
-template <typename T> static inline bool convertDoubleTo(double v, T *value)
+template <typename T> static inline bool convertDoubleTo(double v, T *value, bool allow_precision_upgrade = true)
 {
     Q_STATIC_ASSERT(std::numeric_limits<T>::is_integer);
 
@@ -227,6 +227,10 @@ template <typename T> static inline bool convertDoubleTo(double v, T *value)
         supremum = -2.0 * std::numeric_limits<ST>::min();   // -2 * (-2^63) = 2^64, exact (for T = quint64)
         v = fabs(v);
     }
+    if (std::is_integral<T>::value && sizeof(T) > 4 && !allow_precision_upgrade) {
+        if (v > double(Q_INT64_C(1)<<53) || v < double(-((Q_INT64_C(1)<<53) + 1)))
+            return false;
+    }
 
     *value = std::numeric_limits<T>::max();
     if (v >= supremum)