QRegularExpression::match(QString...) is a performance bottleneck in multithreaded applications

This is a piece of code in a function running concurrently in several threads

static QRegularExpression maxSize("\\[(\\d+)\\]");
QRegularExpression localMaxSize = maxSize;
QRegularExpressionMatch maxSizeMatch = localMaxSize.match(token);

The match function can drastically reduce parallel performances. Indeed, the QRegularExpression::match(QString...) function begins as follows:

d.data()->compilePattern();

QRegularExpressionMatchPrivate *priv = d->doMatch(subject, 0, subject.length(), offset, matchType, matchOptions);
   

The compilePattern() function starts like this:

void QRegularExpressionPrivate::compilePattern()
{
    const QWriteLocker lock(&mutex);

    if (!isDirty)
        return;
    ...

and the doMatch(...) does that on line 1312:

QReadLocker lock(&mutex);

The problem is, as far as I understand it, that compilePattern() places a write lock even when it does not need to write/compile anything (i.e. isDirty is false), preventing all other threads from placing read locks in doMatch(...).
One of the solutions would be to move the write lock after the (!isDirty) check. Then a read lock would be needed before that check.

If you could try to change this locking behavior, that would be great, this problem being one of the performance bottlenecks of my application.