With this, we have complete support for finding integer sample points in FlatAffineConstraints.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D95047
This patch adds support for checking if two PresburgerSets are equal. In particular, one can check if two FlatAffineConstraints are equal by constructing PrebsurgerSets from them and comparing these.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D94915
With this, we have complete support for emptiness checks. This also paves the way for future support to check if two FlatAffineConstraints are equal.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D94272
Subtraction is a foundational arithmetic operation that is often used when computing, for example, data transfer sets or cache hits. Since the result of subtraction need not be a convex polytope, a new class `PresburgerSet` is introduced to represent unions of convex polytopes.
Reviewed By: ftynse, bondhugula
Differential Revision: https://reviews.llvm.org/D87068
This patch adds the capability to perform constraint redundancy checks for `FlatAffineConstraints` using `Simplex`, via a new member function `FlatAffineConstraints::removeRedundantConstraints`. The pre-existing redundancy detection algorithm runs a full rational emptiness check for each inequality separately for checking redundancy. Leveraging the existing `Simplex` infrastructure, in this patch we have an algorithm for redundancy checks that can check each constraint by performing pivots on the tableau, which provides an alternative to running Fourier-Motzkin elimination for each constraint separately.
Differential Revision: https://reviews.llvm.org/D84935
This patch adds the capability to perform exact integer emptiness checks for FlatAffineConstraints using the General Basis Reduction algorithm (GBR). Previously, only a heuristic was available for emptiness checks, which was not guaranteed to always give a conclusive result.
This patch adds a `Simplex` class, which can be constructed using a `FlatAffineConstraints`, and can find an integer sample point (if one exists) using the GBR algorithm. Additionally, it adds two classes `Matrix` and `Fraction`, which are used by `Simplex`.
The integer emptiness check functionality can be accessed through the new `FlatAffineConstraints::isIntegerEmpty()` function, which runs the existing heuristic first and, if that proves to be inconclusive, runs the GBR algorithm to produce a conclusive result.
Differential Revision: https://reviews.llvm.org/D80860
Arjun P