[PATCH] Templatify RegionInfo

[Nadav Rotem]

> On Jul 7, 2014, at 7:46 PM, Chandler Carruth <chandlerc at google.com> wrote:
> 
> So, not really a comment on this specific patch, but how much more effort do we want to push into the region support in LLVM?
> 
> Last time I tried to use the region infrastructure I found it was generally incomplete and no one was happy about relying on dominance frontiers. Are these still significant concerns? What is the path forward? I was easily able to rewrite my code in terms of DominatorTrees instead of regions, and it in some ways became simpler, so I'm not really sold lots of effort going into enhancing the support of regions in the optimizer.

Dominance frontier is one way to compute Region info but the problem is that DF can grow quadratically.  There is a linear algorithm that is based on the Roman Chariots problem[1]. 

[1] - http://dl.acm.org/citation.cfm?id=256217

> 
> Previously, it seemed like the region infrastructure in the optimizer served an important role of making it easy to experiment and explore optimizations in this space without imposing much maintenance burden for such experiments. But pushing the region support down into the machine layer seems much more to do with making this a core part of the expected optimization strategy, so that's why I'm asking now.
> 
> 
> On Mon, Jul 7, 2014 at 6:06 PM, Matt Arsenault <arsenm2 at gmail.com> wrote:
> Hi,
> 
> These patches do the bruteforce work of templatifying RegionInfo / DominanceFrontier so they can be used on MachineBasicBlocks, mostly by trying to mimic what DominatorTree and LoopInfo already do for this. These build, but I haven’t yet gotten to doing anything useful with them yet.
> 
> 
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> 
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20140708/cdde000e/attachment.html>