Formal annotating Code for Optimizations?

[Craig Black]

"Manfred_Nowak" <svv1999 at hotmail.com> wrote in message 
news:g5ptdk$2t8f$1 at digitalmars.com...
> Example:
> If two actions `a1',`a2' are based on a binary decision `b' then on a
> pure logical level one can code:
>
>  if( b)
>    a1.do; // actions have `do'- and `undo'-methods
>  else
>    a2.do;
>
> But if one knows, that the probability of `b' to be `true' is much
> greater than .5, then in order to use the precomputing capabilities
> of the CPU one would probably like to code:
>
>  a1.do;
>  if( !b){
>    a1.undo;
>    a2.do;
>  }
>
> The other case requires similar code.
>
> In this latter code the abstraction of a simple binary decision seems
> to be less obvious, which seems to be bad for maintenance.
>
> Of course one can annotate with comments. But since comments can be
> hints for defencies in the language, the question rises whether one
> should formalize this:
>
>  if( b)note( p(b)>.8)
>    a1.do;
>    undo a1.undo;
>  else
>    a2;
>    undo a2.undo;
>
> -manfred
> -- 
> Maybe some knowledge of some types of disagreeing and their relation
> can turn out to be useful:
> http://blog.createdebate.com/2008/04/07/writing-strong-arguments/

It'll never be implemented, but it's a good idea.  Along the same lines, 
(another good idea that'll never be implemented), is to assign a priority to 
a virtual function.  A higher priority means that the virtual function will 
be called more.  This allows the compiler to optimize out the function 
pointer invokation for high-priority virtual functions.

-Craig