Re: Turning off unrolling to certain loops

[Zdenek Dvorak <rakdver@kam.mff.cuni.cz>]

Hi,

> 2) I was using a simple example:
> 
> #pragma unroll 2
>         for (i=0;i<6;i++)
>         {
>             printf ("Hello world\n");
>         }
> 
> If I do this, instead of transforming the code into :
>         for (i=0;i<3;i++)
>         {
>             printf ("Hello world\n");
>             printf ("Hello world\n");
>         }
> 
> as we could expect, it is transformed into:
>         for (i=0;i<2;i++)
>         {
>             printf ("Hello world\n");
>             printf ("Hello world\n");
>         }
>         for (i=0;i<2;i++)
>         {
>             printf ("Hello world\n");
>         }
> 
> 
> (I am using 4.3.2 currently)
> 
> I am using the tree_unroll_loop function to perform the unrolling and
> it seems to always want to keep that epilogue. Is there a reason for
> this? Or is this a bug of some sorts?

such an epilogue is needed when the # of iterations is not known in the
compile time; it should be fairly easy to modify the unrolling not to
emit it when it is not necessary,

Zdenek