diff --git a/src/corelib/tools/qsimd.cpp b/src/corelib/tools/qsimd.cpp
index 6e3b0f9faf..d7c1d8c4a9 100644
--- a/src/corelib/tools/qsimd.cpp
+++ b/src/corelib/tools/qsimd.cpp
@@ -1,7 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
-** Copyright (C) 2018 Intel Corporation.
+** Copyright (C) 2019 Intel Corporation.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -188,6 +188,8 @@ static inline quint64 detectProcessorFeatures()
 # define PICreg "%%rbx"
 #endif
 
+static bool checkRdrndWorks() noexcept;
+
 static int maxBasicCpuidSupported()
 {
 #if defined(Q_CC_EMSCRIPTEN)
@@ -376,37 +378,8 @@ static quint64 detectProcessorFeatures()
         features &= ~AllAVX512;
     }
 
-#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
-    /**
-     * Some AMD CPUs (e.g. AMD A4-6250J and AMD Ryzen 3000-series) have a
-     * failing random generation instruction, which always returns
-     * 0xffffffff, even when generation was "successful".
-     *
-     * This code checks if hardware random generator generates four consecutive
-     * equal numbers. If it does, then we probably have a failing one and
-     * should disable it completely.
-     *
-     * https://bugreports.qt.io/browse/QTBUG-69423
-     */
-    if (features & CpuFeatureRDRND) {
-        const qsizetype testBufferSize = 4;
-        unsigned testBuffer[4] = {};
-
-        const qsizetype generated = qRandomCpu(testBuffer, testBufferSize);
-
-        if (Q_UNLIKELY(generated == testBufferSize &&
-            testBuffer[0] == testBuffer[1] &&
-            testBuffer[1] == testBuffer[2] &&
-            testBuffer[2] == testBuffer[3])) {
-
-            fprintf(stderr, "WARNING: CPU random generator seem to be failing, disable hardware random number generation\n");
-            fprintf(stderr, "WARNING: RDRND generated: 0x%x 0x%x 0x%x 0x%x\n",
-                    testBuffer[0], testBuffer[1], testBuffer[2], testBuffer[3]);
-
-            features &= ~CpuFeatureRDRND;
-        }
-    }
-#endif
+    if (features & CpuFeatureRDRND && !checkRdrndWorks())
+        features &= ~(CpuFeatureRDRND | CpuFeatureRDSEED);
 
     return features;
 }
@@ -662,15 +635,9 @@ static unsigned *qt_random_rdseed(unsigned *ptr, unsigned *)
 }
 #  endif
 
-QT_FUNCTION_TARGET(RDRND) qsizetype qRandomCpu(void *buffer, qsizetype count) noexcept
+static QT_FUNCTION_TARGET(RDRND) unsigned *qt_random_rdrnd(unsigned *ptr, unsigned *end) noexcept
 {
-    unsigned *ptr = reinterpret_cast<unsigned *>(buffer);
-    unsigned *end = ptr + count;
     int retries = 10;
-
-    if (qCpuHasFeature(RDSEED))
-        ptr = qt_random_rdseed(ptr, end);
-
     while (ptr + sizeof(qregisteruint)/sizeof(*ptr) <= end) {
         if (_rdrandXX_step(reinterpret_cast<qregisteruint *>(ptr)))
             ptr += sizeof(qregisteruint)/sizeof(*ptr);
@@ -688,8 +655,64 @@ QT_FUNCTION_TARGET(RDRND) qsizetype qRandomCpu(void *buffer, qsizetype count) no
     }
 
 out:
+    return ptr;
+}
+
+static QT_FUNCTION_TARGET(RDRND) Q_DECL_COLD_FUNCTION bool checkRdrndWorks() noexcept
+{
+    /*
+     * Some AMD CPUs (e.g. AMD A4-6250J and AMD Ryzen 3000-series) have a
+     * failing random generation instruction, which always returns
+     * 0xffffffff, even when generation was "successful".
+     *
+     * This code checks if hardware random generator generates four consecutive
+     * equal numbers. If it does, then we probably have a failing one and
+     * should disable it completely.
+     *
+     * https://bugreports.qt.io/browse/QTBUG-69423
+     */
+    constexpr qsizetype TestBufferSize = 4;
+    unsigned testBuffer[TestBufferSize] = {};
+
+    unsigned *end = qt_random_rdrnd(testBuffer, testBuffer + TestBufferSize);
+    if (end < testBuffer + 3) {
+        // Random generation didn't produce enough data for us to make a
+        // determination whether it's working or not. Assume it isn't, but
+        // don't print a warning.
+        return false;
+    }
+
+    // Check the results for equality
+    if (testBuffer[0] == testBuffer[1]
+        && testBuffer[0] == testBuffer[2]
+        && end == testBuffer + TestBufferSize && testBuffer[0] == testBuffer[3]) {
+        fprintf(stderr, "WARNING: CPU random generator seem to be failing, "
+                        "disabling hardware random number generation\n"
+                        "WARNING: RDRND generated:");
+        for (unsigned *ptr = testBuffer; ptr < end; ++ptr)
+            fprintf(stderr, " 0x%x", *ptr);
+        fprintf(stderr, "\n");
+        return false;
+    }
+
+    // We're good
+    return true;
+}
+
+QT_FUNCTION_TARGET(RDRND) qsizetype qRandomCpu(void *buffer, qsizetype count) noexcept
+{
+    unsigned *ptr = reinterpret_cast<unsigned *>(buffer);
+    unsigned *end = ptr + count;
+
+    if (qCpuHasFeature(RDSEED))
+        ptr = qt_random_rdseed(ptr, end);
+
+    // fill the buffer with RDRND if RDSEED didn't
+    ptr = qt_random_rdrnd(ptr, end);
     return ptr - reinterpret_cast<unsigned *>(buffer);
 }
-#endif
+#elif defined(Q_PROCESSOR_X86) && !defined(Q_OS_NACL) && !defined(Q_PROCESSOR_ARM)
+static bool checkRdrndWorks() noexcept { return false; }
+#endif // Q_PROCESSOR_X86 && RDRND
 
 QT_END_NAMESPACE