diff --git a/src/corelib/text/qchar.cpp b/src/corelib/text/qchar.cpp
index 052dba39e9c..d7006281614 100644
--- a/src/corelib/text/qchar.cpp
+++ b/src/corelib/text/qchar.cpp
@@ -830,8 +830,9 @@ bool QChar::isPrint(char32_t ucs4) noexcept
 */
 bool QT_FASTCALL QChar::isSpace_helper(char32_t ucs4) noexcept
 {
-    if (ucs4 > LastValidCodePoint)
+    if (ucs4 > MaxSeparatorCodepoint)
         return false;
+
     const int test = FLAG(Separator_Space) |
                      FLAG(Separator_Line) |
                      FLAG(Separator_Paragraph);
diff --git a/src/corelib/text/qunicodetables.cpp b/src/corelib/text/qunicodetables.cpp
index cf4fdb199ea..fd491532f1a 100644
--- a/src/corelib/text/qunicodetables.cpp
+++ b/src/corelib/text/qunicodetables.cpp
@@ -8,6 +8,7 @@
 QT_BEGIN_NAMESPACE
 
 namespace QUnicodeTables {
+static constexpr char32_t MaxSeparatorCodepoint = 0x3000;
 
 static constexpr unsigned short uc_property_trie[] = {
     // [0x0..0x11000)
diff --git a/util/unicode/main.cpp b/util/unicode/main.cpp
index e5d1ad47e08..46a39d2ed96 100644
--- a/util/unicode/main.cpp
+++ b/util/unicode/main.cpp
@@ -1306,6 +1306,7 @@ static QHash<int, int> combiningClassUsage;
 static int maxLowerCaseDiff = 0;
 static int maxUpperCaseDiff = 0;
 static int maxTitleCaseDiff = 0;
+static int maxSeparatorCodepoint = 0;
 
 static void readUnicodeData()
 {
@@ -1366,6 +1367,9 @@ static void readUnicodeData()
 
         UnicodeData &data = UnicodeData::valueRef(codepoint);
         data.p.category = categoryMap.value(properties[UD_Category], QChar::Other_NotAssigned);
+        if (data.p.category == QChar::Separator_Space || data.p.category == QChar::Separator_Line
+                || data.p.category == QChar::Separator_Paragraph)
+            maxSeparatorCodepoint = codepoint;
         data.p.combiningClass = properties[UD_CombiningClass].toInt();
         if (!combiningClassUsage.contains(data.p.combiningClass))
             combiningClassUsage[data.p.combiningClass] = 1;
@@ -2986,7 +2990,12 @@ static QByteArray createPropertyInfo()
     Q_ASSERT(blockMap.size() == BMP_END/BMP_BLOCKSIZE +(SMP_END-BMP_END)/SMP_BLOCKSIZE); // 0x1870
     Q_ASSERT(blockMap.last() + blockMap.size() < (1<<(sizeof(unsigned short)*8)));
 
-    QByteArray out = "static constexpr unsigned short uc_property_trie[] = {\n";
+    QByteArray out;
+    out += "static constexpr char32_t MaxSeparatorCodepoint = 0x";
+    out += QByteArray::number(maxSeparatorCodepoint, 16);
+    out += ";\n";
+
+    out += "\nstatic constexpr unsigned short uc_property_trie[] = {\n";
     // First write the map from blockId to indices of unique blocks:
     out += "    // [0x0..0x" + QByteArray::number(BMP_END, 16) + ")";
     for (int i = 0; i < BMP_END/BMP_BLOCKSIZE; ++i) {
@@ -3702,7 +3711,7 @@ int main(int, char **)
     f.write(note);
     f.write("#include \"qunicodetables_p.h\"\n\n");
     f.write("QT_BEGIN_NAMESPACE\n\n");
-    f.write("namespace QUnicodeTables {\n\n");
+    f.write("namespace QUnicodeTables {\n");
     f.write(properties);
     f.write(specialCases);
     f.write(compositions);