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

[Johannes Doerfert]

On 08/12, Robison, Arch wrote:
> > Remember that this annotation is saying that "the loop *as it is* is 
> > safe in a N vector", but things can change between the annotation 
> > (generally source code pragmas, but could be a Polly thing) and actual 
> > vectorization. 
> 
> Because other transformations might introduce recurrences that break vectorization,
> the "safelen" annotation probably should be structured more like 
> llvm.mem.parallel_loop_access, and be attached to every load/store of interest.
We actually emit the llvm.mem.parallel_loop_access annotations already,
thus emitting the dependency distance (or save vectorization width) in a
similar fashion is no problem at all.

-- 

Johannes Doerfert
Researcher / PhD Student

Compiler Design Lab (Prof. Hack)
Saarland University, Computer Science
Building E1.3, Room 4.26

Tel. +49 (0)681 302-57521 : doerfert at cs.uni-saarland.de
Fax. +49 (0)681 302-3065  : http://www.cdl.uni-saarland.de/people/doerfert
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