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.


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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