//===- AffineStructuresParserTest.cpp - FAC parsing unit tests --*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains tests for parsing IntegerSets to FlatAffineConstraints.
// The tests with invalid input check that the parser only accepts well-formed
// IntegerSets. The tests with well-formed input compare the returned FACs to
// manually constructed FACs with a PresburgerSet equality check.
//
//===----------------------------------------------------------------------===//

#include "./AffineStructuresParser.h"
#include "mlir/Analysis/Presburger/PresburgerSet.h"

#include <gtest/gtest.h>

namespace mlir {

/// Construct a FlatAffineConstraints from a set of inequality, equality, and
/// division onstraints.
static FlatAffineConstraints makeFACFromConstraints(
    unsigned dims, unsigned syms, ArrayRef<SmallVector<int64_t, 4>> ineqs,
    ArrayRef<SmallVector<int64_t, 4>> eqs = {},
    ArrayRef<std::pair<SmallVector<int64_t, 4>, int64_t>> divs = {}) {
  FlatAffineConstraints fac(ineqs.size(), eqs.size(), dims + syms + 1, dims,
                            syms, 0);
  for (const auto &div : divs)
    fac.addLocalFloorDiv(div.first, div.second);
  for (const auto &eq : eqs)
    fac.addEquality(eq);
  for (const auto &ineq : ineqs)
    fac.addInequality(ineq);
  return fac;
}

TEST(ParseFACTest, InvalidInputTest) {
  MLIRContext context;
  FailureOr<FlatAffineConstraints> fac;

  fac = parseIntegerSetToFAC("(x)", &context, false);
  EXPECT_TRUE(failed(fac))
      << "should not accept strings with no constraint list";

  fac = parseIntegerSetToFAC("(x)[] : ())", &context, false);
  EXPECT_TRUE(failed(fac))
      << "should not accept strings that contain remaining characters";

  fac = parseIntegerSetToFAC("(x)[] : (x - >= 0)", &context, false);
  EXPECT_TRUE(failed(fac))
      << "should not accept strings that contain incomplete constraints";

  fac = parseIntegerSetToFAC("(x)[] : (y == 0)", &context, false);
  EXPECT_TRUE(failed(fac))
      << "should not accept strings that contain unkown identifiers";

  fac = parseIntegerSetToFAC("(x, x) : (2 * x >= 0)", &context, false);
  EXPECT_TRUE(failed(fac))
      << "should not accept strings that contain repeated identifier names";

  fac = parseIntegerSetToFAC("(x)[x] : (2 * x >= 0)", &context, false);
  EXPECT_TRUE(failed(fac))
      << "should not accept strings that contain repeated identifier names";

  fac = parseIntegerSetToFAC("(x) : (2 * x + 9223372036854775808 >= 0)",
                             &context, false);
  EXPECT_TRUE(failed(fac)) << "should not accept strings with integer literals "
                              "that do not fit into int64_t";
}

/// Parses and compares the `str` to the `ex`. The equality check is performed
/// by using PresburgerSet::isEqual
static bool parseAndCompare(StringRef str, const FlatAffineConstraints &ex,
                            MLIRContext *context) {
  FailureOr<FlatAffineConstraints> fac = parseIntegerSetToFAC(str, context);

  EXPECT_TRUE(succeeded(fac));

  return PresburgerSet(*fac).isEqual(PresburgerSet(ex));
}

TEST(ParseFACTest, ParseAndCompareTest) {
  MLIRContext context;
  // simple ineq
  EXPECT_TRUE(parseAndCompare(
      "(x)[] : (x >= 0)", makeFACFromConstraints(1, 0, {{1, 0}}), &context));

  // simple eq
  EXPECT_TRUE(parseAndCompare("(x)[] : (x == 0)",
                              makeFACFromConstraints(1, 0, {}, {{1, 0}}),
                              &context));

  // multiple constraints
  EXPECT_TRUE(parseAndCompare("(x)[] : (7 * x >= 0, -7 * x + 5 >= 0)",
                              makeFACFromConstraints(1, 0, {{7, 0}, {-7, 5}}),
                              &context));

  // multiple dimensions
  EXPECT_TRUE(parseAndCompare("(x,y,z)[] : (x + y - z >= 0)",
                              makeFACFromConstraints(3, 0, {{1, 1, -1, 0}}),
                              &context));

  // dimensions and symbols
  EXPECT_TRUE(parseAndCompare(
      "(x,y,z)[a,b] : (x + y - z + 2 * a - 15 * b >= 0)",
      makeFACFromConstraints(3, 2, {{1, 1, -1, 2, -15, 0}}), &context));

  // only symbols
  EXPECT_TRUE(parseAndCompare("()[a] : (2 * a - 4 == 0)",
                              makeFACFromConstraints(0, 1, {}, {{2, -4}}),
                              &context));

  // simple floordiv
  EXPECT_TRUE(parseAndCompare(
      "(x, y) : (y - 3 * ((x + y - 13) floordiv 3) - 42 == 0)",
      makeFACFromConstraints(2, 0, {}, {{0, 1, -3, -42}}, {{{1, 1, -13}, 3}}),
      &context));

  // multiple floordiv
  EXPECT_TRUE(parseAndCompare(
      "(x, y) : (y - x floordiv 3 - y floordiv 2 == 0)",
      makeFACFromConstraints(2, 0, {}, {{0, 1, -1, -1, 0}},
                             {{{1, 0, 0}, 3}, {{0, 1, 0, 0}, 2}}),
      &context));

  // nested floordiv
  EXPECT_TRUE(parseAndCompare(
      "(x, y) : (y - (x + y floordiv 2) floordiv 3 == 0)",
      makeFACFromConstraints(2, 0, {}, {{0, 1, 0, -1, 0}},
                             {{{0, 1, 0}, 2}, {{1, 0, 1, 0}, 3}}),
      &context));
}

} // namespace mlir