[LLVMdev] parallel loop metadata question

[Tobias Grosser]

On 05/05/2014 10:14, Pekka Jääskeläinen wrote:
> On 05/02/2014 07:22 PM, Humphreys, Jonathan wrote:
>> Thanks for the link.  I understand your concern of caution with metadata.
>> I cannot, though, imagine how the dependence relation (independence)
>> of two
>> memory references can be affected by a third memory reference.  If two
>> references are independent across loop iterations, then they are
>> independent, and any other load or store cannot change that.  Right?
>
> Yes, it makes sense. I'm mostly concerned about accesses to stack,
> but even those at this point should remain independent. Otherwise even
> the current semantics might produce broken code with parallel stack
> accesses.
>
> However, as this is such a major semantics change to the original one, I'd
> like to hear more opinions on it. I suggest you create a (documentation)
> patch where the new semantics is articulated and request comments for it at
> the LLVM-commits list.

I agree with both. I think the extension is very reasonable and I also 
do not see a reason why this interpretation should cause troubles. 
However, to get it right it would be good to get this throughly reviewed.

Tobias