llvm dev - Feb 2013 - [LLVMdev] Parallel Loop Metadata

Hi Pekka,

On 2013-02-21, at 4:10 PM, Pekka Jääskeläinen wrote:
> On 02/21/2013 10:12 PM, Redmond, Paul wrote:
>> I've attached some IR which shows what I'm asking about. If you
run this
>> through opt "inner" will be inlined and both loops in
"outer" will have the
>> same loop id metadata..
> 
> In your test case the two loops illegally share a loop id MD (!0) the first
> place, thus the bug is in the producer of the loop MD that created that
> loop metadata.
> 
Ok, that was really what I was trying to ask--do the loop ids need to be unique?
There is nothing preventing this from happening and the documentation
doesn't state this requirement.

paul
> The idea of the loop ID metadata is that it truly is a unique MDNode per
> loop, *universally* (stay unique even after Module linkage). I.e., you
> need to create a new self-referential ID metadata for each loop.
> 
> -- 
> --Pekka

On 02/21/2013 11:15 PM, Redmond, Paul wrote:
> Ok, that was really what I was trying to ask--do the loop ids need to be
> unique? There is nothing preventing this from happening and the
documentation
> doesn't state this requirement.
Yes, it has to be unique for each loop for it to work robustly. True, it's
not stated clearly enough. I'll clarify the documentation for this part.

-- 
--Pekka

On 02/21/2013 11:33 PM, Pekka Jääskeläinen wrote:
> Yes, it has to be unique for each loop for it to work robustly. True,
it's
> not stated clearly enough. I'll clarify the documentation for this
part.
Updated the documentation in r175888.

-- 
Pekka