[llvm-dev] [RFC] Polly Status and Integration

[Michael Kruse via llvm-dev]

2017-10-14 22:30 GMT+02:00 Hongbin Zheng <etherzhhb at gmail.com>:
> I have a feeling that the LLVM LoopInfo/Loop datastructure, which only focus
> on the CFG, is not sufficient.
> And we build extra layer upon the LLVM LoopInfo/Loop, e.g. Scop in Polly and
> the Hierarchical CFG in VPlan (right?).
>
> Maybe we can have layers between the existing LoopInfo/Loop and VPlan/SCoP:
>
> 1. LoopInfo/Loop
> 2. LoopInfo/Loop + Hierarchical CFG
> 3. LoopInfo/Loop + Hierarchical CFG + Memory Accesses description
> 4. VPlan/Scop
>
> I think layer 2 and 3 will be very useful even outside of Polly and VPlan

The idea is also that the new hierarchy can be modified iteratively
and IR only generated at the end when all transform decisions have
been made, and analysis/layers be shared between transformations, eg..
a polyhedral dependency analysis, when available, can be used by the
vectorizer without additional programming because the dependency data
structure is the same. PolyhedralInfo currently is very different from
LoopAccessAnalysis.

Michael