Re: C++ - inlining of functions returning an unwindable object

Hi,


I tried your code with g++ 4.4.1 on amd64. g++ basically emits the
same code for testsimple and testsimple2 and does not call the getter.
I compiled with:
g++ test.cpp -c -O3 -S


Are you sure you turned on all optimizations? Perhaps declaring the
getter as
std::string get() const {
        return s_;
}
helps.


Another important issue is the return value optimizatoin of C++.
http://en.wikipedia.org/wiki/Return_value_optimization (though the
article claims msvc++ supports this feature)


Yet another thing one should not forget is that a language allowing
pointers which may point to literally everywhere, pointer arithmetic
and so on really makes headaches for compiler writers. C/C++
enthusiasts often claim how fast pointers are but this is only the
case if the compiler is _really_ smart. That's why Fortran is
sometimes faster than C. And since std::string uses pointers
internally this may be the reason why msvc++ is not able to inline the
function.


Hope this helped a bit.


- Roland Leissa

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