diff --git a/src/filewidgets/kdiroperator.cpp b/src/filewidgets/kdiroperator.cpp
--- a/src/filewidgets/kdiroperator.cpp
+++ b/src/filewidgets/kdiroperator.cpp
@@ -45,6 +45,7 @@
 #include <QTimer>
 #include <QDebug>
 #include <QMimeDatabase>
+#include <QRegularExpression>
 #include <QStack>
 
 #include <kdirlister.h>
@@ -1463,49 +1464,44 @@
         return false;
     }
 
-    QStringList mimeTypes = dirLister->mimeFilters();
-    const QStringList nameFilter = dirLister->nameFilter().split(QLatin1Char(' '), QString::SkipEmptyParts);
-    QMimeDatabase db;
+    const QStringList mimeTypes = dirLister->mimeFilters();
+    const QStringList nameFilters = dirLister->nameFilter().split(QLatin1Char(' '), QString::SkipEmptyParts);
 
-    if (mimeTypes.isEmpty() && nameFilter.isEmpty() && !supported.isEmpty()) {
+    if (mimeTypes.isEmpty() && nameFilters.isEmpty() && !supported.isEmpty()) {
         return true;
     } else {
-        QRegExp r;
-        r.setPatternSyntax(QRegExp::Wildcard);   // the "mimetype" can be "image/*"
+        QMimeDatabase db;
+        QRegularExpression re;
 
         if (!mimeTypes.isEmpty()) {
-            QStringList::ConstIterator it = supported.begin();
+            for (const QString &str : supported) {
+                // wilcard matching because the "mimetype" can be "image/*"
+                re.setPattern(QRegularExpression::wildcardToRegularExpression(str));
 
-            for (; it != supported.end(); ++it) {
-                r.setPattern(*it);
-
-                QStringList result = mimeTypes.filter(r);
-                if (!result.isEmpty()) {   // matches! -> we want previews
+                if (mimeTypes.indexOf(re) != -1) {  // matches! -> we want previews
                     return true;
                 }
             }
         }
 
-        if (!nameFilter.isEmpty()) {
+        if (!nameFilters.isEmpty()) {
             // find the mimetypes of all the filter-patterns
-            QStringList::const_iterator it1 = nameFilter.begin();
-            for (; it1 != nameFilter.end(); ++it1) {
-                if ((*it1) == QLatin1String("*")) {
+            for (const QString &filter : nameFilters) {
+                if (filter == QLatin1Char('*')) {
                     return true;
                 }
 
-                QMimeType mt = db.mimeTypeForFile(*it1, QMimeDatabase::MatchExtension /*fast mode, no file contents exist*/);
+                const QMimeType mt = db.mimeTypeForFile(filter, QMimeDatabase::MatchExtension /*fast mode, no file contents exist*/);
                 if (!mt.isValid()) {
                     continue;
                 }
-                QString mime = mt.name();
+                const QString mime = mt.name();
 
+                for (const QString &str : supported) {
                 // the "mimetypes" we get from the PreviewJob can be "image/*"
                 // so we need to check in wildcard mode
-                QStringList::ConstIterator it2 = supported.begin();
-                for (; it2 != supported.end(); ++it2) {
-                    r.setPattern(*it2);
-                    if (r.indexIn(mime) != -1) {
+                    re.setPattern(QRegularExpression::wildcardToRegularExpression(str));
+                    if (re.match(mime).hasMatch()) {
                         return true;
                     }
                 }
diff --git a/src/filewidgets/kfilewidget.cpp b/src/filewidgets/kfilewidget.cpp
--- a/src/filewidgets/kfilewidget.cpp
+++ b/src/filewidgets/kfilewidget.cpp
@@ -2451,11 +2451,15 @@
 
 QString KFileWidgetPrivate::findMatchingFilter(const QString &filter, const QString &filename) const
 {
-    const QStringList patterns = filter.left(filter.indexOf(QLatin1Char('|'))).split(QLatin1Char(' '), QString::SkipEmptyParts);       // '*.foo *.bar|Foo type' -> '*.foo', '*.bar'
+     // e.g.: '*.foo *.bar|Foo type' -> '*.foo', '*.bar'
+    const QStringList patterns = filter.left(filter.indexOf(QLatin1Char('|'))).split(QLatin1Char(' '),
+                                             QString::SkipEmptyParts);
+
+    QRegularExpression rx;
     for (const QString &p : patterns) {
-        QRegExp rx(p);
-        rx.setPatternSyntax(QRegExp::Wildcard);
-        if (rx.exactMatch(filename)) {
+        rx.setPattern(QRegularExpression::anchoredPattern(
+                                        QRegularExpression::wildcardToRegularExpression(p)));
+        if (rx.match(filename).hasMatch()) {
             return p;
         }
     }