Re: C++: pointer to member as template argument and inline

["Kristian Spangsege" <kristian dot spangsege at gmail dot com>]

It seems the answer to my question is "no" :-(

With GCC 4.0.2 (using -O3) the call to 'inc' does not get inlined in
following code:

struct S
{
 int inc(int v)
 {
   return v+1;
 }

 template<int (S::*f)(int)> int call(int v)
 {
   return (this->*f)(v);
 }

 int func(int v)
 {
   return call<&S::inc>(v);
 }
};

int main()
{
 S s;

 return s.func(6);
}



This is kind of surprising since in this next example the call to
'inc' does get inlined:

int inc(int v)
{
 return v+1;
}

template<int (*f)(int)> int call(int v)
{
 return (*f)(v);
}

int func(int v)
{
 return call<&inc>(v);
}

int main()
{
 return func(6);
}


Why does GCC optimizer discriminate between these two scenarios so
drasticly? I wonder if this is intensionally...


On 8/6/06, Kristian Spangsege <kristian.spangsege@gmail.com> wrote:
> Hi,
>
> Is GCC able to inline a method when that method is passed as a
> pointer-to-member template argument and then called with the syntax
> (this->*foo)(...) ?


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