c++ - Improving readability without losing performance? -

let's assume have 3 functions f0, f1, f2 take 3 arguments. let's assume have big function bigfunc call, takes return values first 3 functions arguments.

i may want make call this:

bigfunc(f0(arg0, arg1, arg2), f1(arg3, arg4, arg5), f2(arg6, arg7, arg8)); 

this big call, think far more readable write this:

auto bigarg0 = f0(arg0, arg1, arg2); auto bigarg1 = f1(arg3, arg4, arg5); auto bigarg2 = f2(arg6, arg7, arg8);  bigfunc(bigarg0, bigarg1, bigarg2); 

that's great if names bigarg0, bigarg1, bigarg2 allow me more specific doing (for example if f0, f1, f2 bit generic; can think of stl algorithms, different things depending of type of iterators give it).

the problem this, however, naming bigarg0, bigarg1, bigarg2, make them not temporaries anymore, (i suppose) harder compiler optimize.

so, here question: what right way this, if don't want lose performance? make bigarg0, bigarg1, bigarg2 const? give arguments bigfunc through std::move? bit of both?

do destructor , copy-constructor of return values have observable behavior standard defines them?

if don't , compiler has neccessary info prove it, compiler can ellide copy without needing rvo exception.

perhaps that's case if use std::move? either way moving might better copying...

or perhaps bigfunc gets arguments constant reference, in case both ways result in same code anyway...