Sam James <sam@gentoo.org> writes:

> Alexe Stefan <stefanalexe48@gmail.com> writes:
>
>> Does enabling USE=valgrind impact runtime performance in any way?
>
> A very small amount because it adds a check at runtime for whether
> the application is running under Valgrind. The compiler may be able
> to optimise this a bit if it can determine it's unlikely (if the
> Valgrind headers don't already do this, they should probably mark
> them as cold functions).

Sorry, I should say, they're hot functions but the if()s for them
should be unlikely()'d.