Expose the SCEVAffinator and make it a member the SCoP class

[jdoerfert]

Summary

This change has three major advantages:
  + The ScopInfo.cpp becomes smaller.
  + It allows to use the SCEVAffinator from outside the ScopInfo.
  + A member object allows state which in turn allows e.g., caching.

[grosser]

This looks good to me.

There is just a TODO that you forgot in one @brief comment.

Best,
Tobias

[Meinersbur]

include/polly/ScopInfo.h

784 ↗

(On Diff #31909)

Could the Affinator object be owned by ScopStmt s.t. D11975 can key only for the SCEV?

include/polly/Support/SCEVAffinator.h

52 ↗

(On Diff #31909)

@return?

polly/trunk/include/polly/Support/SCEVAffinator.h

 struct SCEVAffinator : public llvm::SCEVVisitor<SCEVAffinator, isl_pw_aff *> {
 public:
   SCEVAffinator(Scop *S);
 
   /// @brief Translate a SCEV to an isl_pw_aff.
   ///
   /// @param E    The expression that is translated.
   /// @param Stmt The SCoP statment surrounding @p E.
+  ///
+  /// @returns The isl representation of the SCEV @p E in @p Stmt.
   __isl_give isl_pw_aff *getPwAff(const llvm::SCEV *E, const ScopStmt *Stmt);
 
 private:
   Scop *S;
   isl_ctx *Ctx;
   unsigned NumIterators;
   const llvm::Region &R;
   llvm::ScalarEvolution &SE;