[MLIR][Presburger] Refactor MultiAffineFunction to be defined over universe
This patch refactors MAF to be defined over the universe in a given space
instead of being defined over a restricted domain.
The reasoning for this refactor is to store division representation for local
variables explicitly for the function outputs. This change is required for
unionLexMax/Min to support local variables which will be upstreamed after this
patch. Another reason for this refactor is to have a flattened form of
AffineMap as MultiAffineFunction.
Reviewed By: arjunp
Differential Revision: https://reviews.llvm.org/D131864
14 files changed: