diff --git a/src/corelib/tools/qstringalgorithms_p.h b/src/corelib/tools/qstringalgorithms_p.h
index b4be5c7ec7..65901b0286 100644
--- a/src/corelib/tools/qstringalgorithms_p.h
+++ b/src/corelib/tools/qstringalgorithms_p.h
@@ -120,21 +120,23 @@ template <typename StringType> struct QStringAlgorithms
 
         Char *dst = const_cast<Char *>(result.cbegin());
         Char *ptr = dst;
+        bool unmodified = true;
         forever {
             while (src != end && isSpace(*src))
                 ++src;
             while (src != end && !isSpace(*src))
                 *ptr++ = *src++;
-            if (src != end)
-                *ptr++ = QChar::Space;
-            else
+            if (src == end)
                 break;
+            if (*src != QChar::Space)
+                unmodified = false;
+            *ptr++ = QChar::Space;
         }
         if (ptr != dst && ptr[-1] == QChar::Space)
             --ptr;
 
         int newlen = ptr - dst;
-        if (isConst && newlen == str.size()) {
+        if (isConst && newlen == str.size() && unmodified) {
             // nothing happened, return the original
             return str;
         }
diff --git a/tests/auto/corelib/tools/qstring/tst_qstring.cpp b/tests/auto/corelib/tools/qstring/tst_qstring.cpp
index 8cd9610542..d2f7a6ee50 100644
--- a/tests/auto/corelib/tools/qstring/tst_qstring.cpp
+++ b/tests/auto/corelib/tools/qstring/tst_qstring.cpp
@@ -2033,6 +2033,8 @@ void tst_QString::simplified_data()
     QTest::newRow("chars apart posttab") << "a \tb" << "a b";
     QTest::newRow("chars apart pretab") << "a\t b" << "a b";
     QTest::newRow("many words") << "  just some    random\ttext here" << "just some random text here";
+    QTest::newRow("newlines") << "a\nb\nc" << "a b c";
+    QTest::newRow("newlines-trailing") << "a\nb\nc\n" << "a b c";
 }
 
 void tst_QString::simplified()