Turning off unrolling to certain loops

Jean Christophe Beyler jean.christophe.beyler@gmail.com
Tue Oct 6 13:34:00 GMT 2009


Yes, I'd be happy to look into how you did it or where you were up to.

I don't know what I'll be able to do but it might lead me in the right
direction and allow me to finish what you started.

Thanks,
Jc

On Tue, Oct 6, 2009 at 2:53 AM, Zdenek Dvorak <rakdver@kam.mff.cuni.cz> wrote:
> Hi,
>
>> I was wondering if it was possible to turn off the unrolling to
>> certain loops. Basically, I'd like the compiler not to consider
>> certain loops for unrolling but fail to see how exactly I can achieve
>> that.
>>
>> I've traced the unrolling code to multiple places in the code (I'm
>> working with the 4.3.2 version) and, for the moment, I'm trying to
>> figure out if I can add something in the loop such as a note that I
>> can later find in the FOR_EACH_LOOP loops in order to turn the
>> unrolling for that particular loop off.
>>
>> Have you got any ideas of what I could use like "note" or even a
>> better idea all together?
>
> the normal way of doing this is using a #pragma.  For instance,
> icc implements #pragma nounroll for this purpose.  I have some prototype
> implementation for gcc, I can send it to you if you were interested in
> finishing it,
>
> Zdenek
>



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