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Re: [patch] Statement operand iterators


> > here is the reimplementation of the idea.  The thing now uses macros in
> > such a way that gcc is able to determine in compile time which type of
> > operands is accessed.  The macros make it a small bit harder to use --
> > the example I used in the first mail would now be written as
> >
> > oii oi;
> >   {
> >     code;
> >   });
> >
> > with the negative effects of this type of macros (hard to
> > debug, impossible to use #ifs in code); but at least (unlike
> > EXECUTE_IF_SET_IN_BITMAP macro) `break' in code will work as expected.
> >
> > On the other hand, it no longer causes any measurable slowdowns.
> Macros which take compound statements as arguments are trouble -
> mainly because the preprocessor doesn't count braces when looking for
> the close paren.  I would strongly encourage you to implement this in
> a way that allows writing
>   oii oi;
>     {
>       code;
>     }
> I think you could achieve this by moving the bulk of the macros into
> oi_init and oi_next (which are inline, so there should be no
> performance hit).  

unfortunately this cannot be done; the performance penalty for having to
decide which type of operands you are accessing is too high (see the
previous incarnation of the patch that avoided the use of macros


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