Small sibbling call tweak

[Jan Hubicka]

> Hi,
> 
> Many thanks to the folks who implemented sibling call optimization!
> 
> However, there's still room for improvement.  Way back on May 9th,
> Jan Hubicka <jh@suse.cz> posted a suggestion:
> 
> > The sibbling call sequence is not generated for calls appearing
> > lexically inside loops.  This is not good idea IMO, since it is
> > common practice to have loop with conditional return inside
> > such as:
> > 
> > main()
> > { while (1) if (q()) return t();
> > }
> 
> I agree with this.  Furthermore, when using macros, it is also very
> common to have code enclosed inside `do { ... } while (0)', and the
> current code prevents optimization in that case too.
> 
> Jan included a patch with his email, and Richard Henderson replied
> "OK", but the patch still hasn't been committed.  Is there any
> reason for this?  If not, could someone please commit it?
I see - I need to go trought all my patches and verify they are applied.
I will apply this today.
Some of my patches didn't went in because of some additional issues that
delayed me from applying them. In this case I've had grand plans about
calls.c, that didn't realized quite yet.

Thanks for noticing!

Honza