What about static loops.  These would be loops that would be guaranteed to be unrolled (or at least checked/optimised at compile-time).   If the compiler can't work out all the specifications at compile time then it would be a compile-time error.

form:
static for (int n=0; n<6; n++)
{
 ...
}


void func(int size)
{
    static for (int n=0; n<size; n++) //Compile time error - "Variable size cannot be determined at compile-time, for a static loop"
   {

    }

}


The compiler wouldn't necessarily unroll the for-loop.  It would just be checked to make sure it can.   One use would be for compile-time property deduction that has been discussed recently.  Another reason would be to make sure that a particular loop can be optimised.

C/C++ has an unroll pragma. I think this would simply be a stronger (slightly different) version of that.

-- 
-Anderson: http://badmama.com.au/~anderson/

unrolled loops arent neccessarily faster on todays higly complex pc architectures. I bet a modern pentium would probably cache instructions that were repeatedly executed - so unroll loops would actually be slower.

In article <c7hjcc$2hph$1@digitaldaemon.com>, J Anderson says...
>
>What about static loops.  These would be loops that would be guaranteed to be unrolled (or at least checked/optimised at compile-time).   If the compiler can't work out all the specifications at compile time then it would be a compile-time error.
>
>form:
>static for (int n=0; n<6; n++)
>{
>  ...
>}
>
>
>void func(int size)
>{
>     static for (int n=0; n<size; n++) //Compile time error - "Variable
>size cannot be determined at compile-time, for a static loop"
>    {
>
>     }
>
>}
>
>
>The compiler wouldn't necessarily unroll the for-loop.  It would just be checked to make sure it can.   One use would be for compile-time property deduction that has been discussed recently.  Another reason would be to make sure that a particular loop can be optimised.
>
>C/C++ has an unroll pragma. I think this would simply be a stronger (slightly different) version of that.
>
>-- 
>-Anderson: http://badmama.com.au/~anderson/

imr1984 wrote:

>unrolled loops arent neccessarily faster on todays higly complex pc
>architectures. I bet a modern pentium would probably cache instructions that
>were repeatedly executed - so unroll loops would actually be slower.
>
>  
>

I'm not necessarily taking about unrolling loops.  It's just that loops that can be unrolled can be optimised in other ways at compile time.  It would be nice to know that a look remains static.

-- 
-Anderson: http://badmama.com.au/~anderson/

In article <c7hjcc$2hph$1@digitaldaemon.com>, J Anderson says...
>
>What about static loops.  These would be loops that would be guaranteed to be unrolled (or at least checked/optimised at compile-time).   If the compiler can't work out all the specifications at compile time then it would be a compile-time error.
>
>form:
>static for (int n=0; n<6; n++)
>{
>  ...
>}

I would prefer that the compiler implementation figure out what is best for the target architecture. The less "hints" I have to give to the compiler the better for portability, etc. Let the best compiler writers win.

Mark T wrote:

>In article <c7hjcc$2hph$1@digitaldaemon.com>, J Anderson says...
>  
>
>>What about static loops.  These would be loops that would be guaranteed to be unrolled (or at least checked/optimised at compile-time).   If the compiler can't work out all the specifications at compile time then it would be a compile-time error.
>>
>>form:
>>static for (int n=0; n<6; n++)
>>{
>> ...
>>}
>>    
>>
>
>I would prefer that the compiler implementation figure out what is best for the
>target architecture. The less "hints" I have to give to the compiler the better
>for portability, etc. Let the best compiler writers win. 
>  
>
Right probably a bad idea.  The reason I brought this up was because Kevin Bealer was bring up a whole new for-loop construct, for an idea I liked (iterating over properties at compile-time).  I don't think a new for-loop would be a good idea but if people can't agree that a general for-loop is good enough, I think something in-between would be good.

-- 
-Anderson: http://badmama.com.au/~anderson/