GIMPLE Question

[Joe Buck]

On Fri, Feb 25, 2011 at 11:33:58AM -0800, Andrew Pinski wrote:
> On Fri, Feb 25, 2011 at 11:21 AM, Kyle Girard <kyle@kdmanalytics.com> wrote:
> >
> >> Â  That *is* the content of the bar method. Â What exactly do you expect to see
> >> happening when you assign a class with no members? Â There's nothing to do!
> >
> >
> > I was hoping to see the assignment. Â My example might have been a little
> > too simple. Â Here's a slightly more complex example:
> >
> > foo.hh
> >
> > class A
> > {
> > public:
> > Â  void yay(){};
> > };
> 
> A is still an empty class, try adding "int a;" and you will see some code there.

The fact that passing an empty class has zero cost is used quite a bit in
the design of the standard library to generate efficient specialized
templates.  The empty objects are just used to select the correct
overloaded form.