[LLVMdev] Proposal for ""llvm.mem.vectorize.safelen"

[Renato Golin]

On 12 August 2014 22:09, Johannes Doerfert <doerfert at cs.uni-saarland.de> wrote:
> We could actually generate (very simple) vector code ourself instead
> of relying on the vectorizer. Furthermore, we could directly utilize the
> heuristics and vector codegen of the vectorizer in Polly instead of
> relying on the robustness of annotations. However, I think the
> annotation way is easier to maintain (as we need it for source
> annotations anyway).

In our previous incarnations of such discussions, the general
consensus was that duplicating the vectorization machinery into Polly
(I believe there is already some) would be a waste of efforts. The
best course of action would be to annotate correctly (like Arch said,
on instructions not basic blocks) and get the vectorizer to do a sweep
scan on all interesting metadata and trim at the lowest common
denominator or whatever the semantics demands.


> Are these slides public?

I don't remember. Arnold, do you still have those, or some scribblings
on that area?

cheers,
--renato