I don’t know if there are statistics showing the difference between C, C++ and Haxe, but maybe the maintainer of the CPP target might have some more insight in that area.
However, I can tell about the approach we usually take when it comes to using Haxe or other high level language tech that compiles to C++.
Regarding performance of the Haxe CPP target you would most likely be able to get better performance by writing directly in C/C++, if you had the all the time in the world and the best C/C++ programmers - so that’s not an option for most companies.
But our experience is at the same time also that you don’t need to have 100% of your code to be super performant - normally you will be able to identify some critical parts of your application, that need to perform really well, and these are usually a very little percentage of the whole code base.
And one solution, is to write these parts directly in for example C or C++ and provide externs for Haxe to interface with that code.
You could say that Haxe is a super, super, super high quality swiss army knife that can do a most things really really well - and it’s pretty fast to develop in. Just the speed of the compiler, is something that put a smile on your face every day.
But for some cases, it’s better to use the super specialized tool, from the bottom of the tool box instead of trying to modify the swiss army knife to do the job.