Using exception specifications to help compiler

[Wolfgang Bangerth]

> The compiler can optimize successfully only if all functions called by
> the "throw ()" function also have "throw ()" -- or can be inlined, and
> do do not throw exceptions.
> 
> I suspect that in your case, you have something like:
> 
>   void f();
>   void g() throw () { f(); }
> 
> In that case, the "throw ()" on "g" will actually make it bigger -- it
> must now catch any exception thrown by "f" and call "unexpected".  That
> would possibly also account for the slowdown, if you got worse cache
> performance.

I was aware of that, so I started bottom-up. Most of the functions I 
marked were small accessor functions and functions that do not call other 
functions.


> The other possibility is that the additional "throw ()" specifications
> are causing the compiler to do more inlining, which is causing worse
> performance in your particular case.

I don't think that was the case, since code size actually decreased.

Any more hints?

Thanks
  W.

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Wolfgang Bangerth              email:            bangerth@ices.utexas.edu
                               www: http://www.ices.utexas.edu/~bangerth/