[Polly] Remove PolyhedralInfo

[Meinersbur]

PolyhedralInfo is tied to the legacy pass manager. With the eventual removal of the legacy pass manager it will not be useful anymore.

PolyhedralInfo was an experiment to make Polly's analysis available to other passes. Its power is limited due to not being able to make assumptions for which regular Polly would emit a runtime condition/code versioning during optimization.

When eventually porting such an API to the new pass manager, we will have to invent a new API.

[sebpop]

Its power is limited due to not being able to make assumptions for which regular Polly would emit a runtime condition/code versioning during optimization.

When eventually porting such an API to the new pass manager, we will have to invent a new API.

What about adopting the same interface as DA uses for runtime assumptions: SCEVPredicate can be used to pass down to the user all runtime assumptions, and the user can decide whether to version or not based on how complex the assumptions are.

[Meinersbur]

Polly assumptions are not SCEVPredicates, but no-overflow builtins, no-alias ranges, and isl_ast_exprs. The pass down must also match the llvm::Region as Polly does.

At this point PolyhedralInfo is just not useful. If you decide to work on this, feel free to resurrect it but at the moment it is just a burden to move away from the LPM.