70 lines · cpp
1//===- LinearTransform.cpp - MLIR LinearTransform Class -------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "mlir/Analysis/Presburger/LinearTransform.h"10#include "mlir/Analysis/Presburger/IntegerRelation.h"11#include "mlir/Analysis/Presburger/Matrix.h"12#include <utility>13 14using namespace mlir;15using namespace presburger;16 17LinearTransform::LinearTransform(IntMatrix &&oMatrix) : matrix(oMatrix) {}18LinearTransform::LinearTransform(const IntMatrix &oMatrix) : matrix(oMatrix) {}19 20std::pair<unsigned, LinearTransform>21LinearTransform::makeTransformToColumnEchelon(const IntMatrix &m) {22 // Compute the hermite normal form of m. This, is by definition, is in column23 // echelon form.24 auto [h, u] = m.computeHermiteNormalForm();25 26 // Since the matrix is in column ecehlon form, a zero column means the rest of27 // the columns are zero. Thus, once we find a zero column, we can stop.28 unsigned col, e;29 for (col = 0, e = m.getNumColumns(); col < e; ++col) {30 bool zeroCol = true;31 for (unsigned row = 0, f = m.getNumRows(); row < f; ++row) {32 if (h(row, col) != 0) {33 zeroCol = false;34 break;35 }36 }37 38 if (zeroCol)39 break;40 }41 42 return {col, LinearTransform(std::move(u))};43}44 45IntegerRelation LinearTransform::applyTo(const IntegerRelation &rel) const {46 IntegerRelation result(rel.getSpace());47 48 for (unsigned i = 0, e = rel.getNumEqualities(); i < e; ++i) {49 ArrayRef<DynamicAPInt> eq = rel.getEquality(i);50 51 const DynamicAPInt &c = eq.back();52 53 SmallVector<DynamicAPInt, 8> newEq = preMultiplyWithRow(eq.drop_back());54 newEq.emplace_back(c);55 result.addEquality(newEq);56 }57 58 for (unsigned i = 0, e = rel.getNumInequalities(); i < e; ++i) {59 ArrayRef<DynamicAPInt> ineq = rel.getInequality(i);60 61 const DynamicAPInt &c = ineq.back();62 63 SmallVector<DynamicAPInt, 8> newIneq = preMultiplyWithRow(ineq.drop_back());64 newIneq.emplace_back(c);65 result.addInequality(newIneq);66 }67 68 return result;69}70