[LLVMdev] loop vectorizer

[Nadav Rotem]

Hi Frank, 

> 
> To answer Nadav's question. This kind of loop is generated by a scientific library and we are in the process of evaluating whether LLVM can be used for this research project. The target architectures will have (very wide) vector instructions and these loops are performance-critical to the application. Thus it would be important that these loops can make use of the vector units.

Does your CPU have a good scatter/gather support ?  It will be easy to add support for scatter/gather operations to the LLVM Loop-Vectorizer.  The current design focuses on SIMD vectors and it probably does not have all of the features that are needed for wide-vector vectorization. 

> Right now as it seems LLVM cannot vectorize these loops. We might have some time to look into this, but it's not sure yet. However, high-level guidance from LLVM pros would be very useful.
> 
> What is this usual way of requesting an improvement feature? Is this mailing list the central pace to communicate?
> 

You can open bugs on bugzilla, but I think that the best way to move forward is to continue the discussions on the mailing list.  Are there other workloads that are important to you ?  Are there any other problems that you ran into ?

Thanks,
Nadav
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