PATCH: WIP SLPVectorize: Enable vectorization of allocas

[Nadav Rotem]

Hi Tom, 

I am not sure that it is a good idea to generate ExtractElement instructions with dynamic indices at IR level.  I think that this kind of patterns should be matched during instruction selection. Assuming that you can pattern match it during isel, you are still left with the alloca.  Allocas are lowered into stack slots and I think that we should be able to move stack slots that are only stored to. 

Thanks,
Nadav


On Oct 24, 2013, at 9:02 PM, Tom Stellard <tom at stellard.net> wrote:

> Hi,
> 
> As a follow up to this discussion:
> http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-October/066780.html
> 
> I put together a very simple patch that begins to implement the transformation
> mentioned in the llvm-dev thread.  The patch is incomplete and is mostly comments
> with question about how to do certain things, but it does work for the
> simple test case included in the patch.
> 
> I'd appreciate any feedback people can give me on this patch and the
> questions posed in the comments.
> 
> Thanks,
> Tom
> <vectorize-alloca.diff>