This patch adds hermite normal form computation to Matrix. Part of this algorithm
lived in LinearTransform, being used for compuing column echelon form. This
patch moves the implementation to Matrix::hermiteNormalForm and generalises it
to compute the hermite normal form.
Reviewed By: arjunp
Differential Revision: https://reviews.llvm.org/D133510
Only the main Presburger library under the Presburger directory has been switched to use arbitrary precision. Users have been changed to just cast returned values back to int64_t or to use newly added convenience functions that perform the same cast internally.
The performance impact of this has been tested by checking test runtimes after copy-pasting 100 copies of each function. Affine/simplify-structures.mlir goes from 0.76s to 0.80s after this patch. Its performance sees no regression compared to its original performance at commit 18a06d4f3a7474d062d1fe7d405813ed2e40b4fc before a series of patches that I landed to offset the performance overhead of switching to arbitrary precision.
Affine/canonicalize.mlir and SCF/canonicalize.mlir show no noticable difference, staying at 2.02s and about 2.35s respectively.
Also, for Affine and SCF tests as a whole (no copy-pasting), the runtime remains about 0.09s on average before and after.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D129510
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
This patch refactors existing implementations of division representation storage
into a new class, DivisionRepr. This refactoring is done so that the common
division utilities can be shared in an upcoming patch.
Reviewed By: arjunp
Differential Revision: https://reviews.llvm.org/D129146
Normalize some of the division and inequality expressions used,
which can improve performance. Also deduplicate some of the
normalization functionality throughout the Presburger library.
Reviewed By: Groverkss
Differential Revision: https://reviews.llvm.org/D123314
Add support for computing the symbolic integer lexmin of a polyhedron.
This finds, for every assignment to the symbols, the lexicographically
minimum value attained by the dimensions. For example, the symbolic lexmin
of the set
`(x, y)[a, b, c] : (a <= x, b <= x, x <= c)`
can be written as
```
x = a if b <= a, a <= c
x = b if a < b, b <= c
```
This also finds the set of assignments to the symbols that make the lexmin unbounded.
This was previously landed in da92f92621e28a56fe8ad79d82eb60e436bf1d39 and
reverted in b238c252e8b1bbebc7ed79c08e06c23514d0dfb4 due to a build failure
in the code. Re-landing now with a fixed build.
Reviewed By: Groverkss
Differential Revision: https://reviews.llvm.org/D122985
Add support for computing the symbolic integer lexmin of a polyhedron.
This finds, for every assignment to the symbols, the lexicographically
minimum value attained by the dimensions. For example, the symbolic lexmin
of the set
`(x, y)[a, b, c] : (a <= x, b <= x, x <= c)`
can be written as
```
x = a if b <= a, a <= c
x = b if a < b, b <= c
```
This also finds the set of assignments to the symbols that make the lexmin unbounded.
Reviewed By: Groverkss
Differential Revision: https://reviews.llvm.org/D122985
This patch replaces various functions over inequalities/equalities in
IntegerPolyhedron with Matrix functions already implementing them or refactors
them to a Matrix function.
Reviewed By: arjunp
Differential Revision: https://reviews.llvm.org/D120482
This patch moves the Presburger library to a new `presburger` namespace.
This allows to shorten some names, helps to avoid polluting the mlir namespace,
and also provides some structure.
Reviewed By: arjunp
Differential Revision: https://reviews.llvm.org/D120505
This patch introduces a class LexSimplex that can currently be used to find the
lexicographically minimal rational point in an IntegerPolyhedron. This is a
series of patches leading to computing the lexicographically minimal integer
lattice point as well parametric lexicographic minimization.
Reviewed By: Groverkss
Differential Revision: https://reviews.llvm.org/D117437
This results in significant deduplication of code. This patch is not expected to change any functionality, it's just some simplification in preparation for future work. Also slightly simplified some code that was being touched anyway and added some unit tests for some functions that were touched.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D105152
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
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
