And more while at it: for latin1 strings used in concatenation it is recommended to use QLatin1String and for single chars QLatin1Char. QStringLiteral is more expensive here, and QStringBuilder & QString has proper overloads for the concatenations. So you want to keep the QLatin1Strings and rather turn those for single chars to QLatin1Char.

Edit: and same for == comparisons

There is indeed a QString overload for concatenating QLatin1String, but it will have to be converted char-by-char (from 8 bits to 16 bits), so isn't it faster to concatenate QStringLiterals?

In D26868#602150, @dfaure wrote:

There is indeed a QString overload for concatenating QLatin1String, but it will have to be converted char-by-char (from 8 bits to 16 bits), so isn't it faster to concatenate QStringLiterals?

I have never seen numbers, but any time I asked someone who might have seen numbers, they told me: QStringLiteral only for final strings not further modified or given to operations. Sadly cannot find references now, but I asked often the recent years.
Looking at the code, the qt_from_latin1 helper method might be as efficient on most processors as the memcpy is perhaps, and making up for any other overhead the QStringLiteral-generated code has, perhaps atomic stuff around the generated QString instance is expensive compared to the copy logic?

But ready to hear from real Qt experts once more, perhaps with numbers this time :)

In D26868#602162, @kossebau wrote:

In D26868#602150, @dfaure wrote:

There is indeed a QString overload for concatenating QLatin1String, but it will have to be converted char-by-char (from 8 bits to 16 bits), so isn't it faster to concatenate QStringLiterals?

I have never seen numbers, but any time I asked someone who might have seen numbers, they told me: QStringLiteral only for final strings not further modified or given to operations. Sadly cannot find references now, but I asked often the recent years.
Looking at the code, the qt_from_latin1 helper method might be as efficient on most processors as the memcpy is perhaps, and making up for any other overhead the QStringLiteral-generated code has, perhaps atomic stuff around the generated QString instance is expensive compared to the copy logic?

But ready to hear from real Qt experts once more, perhaps with numbers this time :)

I checked here with a really big xml file and the difference seems negligible. ( QStringLiteral 0.0s and QLatin1String 0.0s ) - I'd use QStringLiteral just for the sake of consistency across the codebase, tough

Also compared binary size? ;) You still want to use QLatin1Char with single characters, that is less undisputed agreed upon as better choice :)