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// SPDX-License-Identifier: GPL-3.0-or-later
#include "rcc/CodeGen/PBQP/Graph.h"
#include "rcc/CodeGen/PBQP/Math.h"
#include "rcc/CodeGen/PBQP/Solver.h"
#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <iostream>
#include <string_view>
#include <vector>
namespace {
class TestContext final {
public:
void expect(bool Condition, std::string_view Message) {
if (Condition)
return;
std::cerr << Message << '\n';
++Failures;
}
[[nodiscard]] int result() const noexcept {
return Failures == 0 ? 0 : 1;
}
private:
int Failures = 0;
};
void testMath(TestContext &Context) {
using namespace rcc::pbqp;
Context.expect(
addCosts(InfiniteCost, -4) == InfiniteCost && addCosts(InfiniteCost - 1, 2) == InfiniteCost &&
addCosts(NegativeInfiniteCost + 1, -2) == NegativeInfiniteCost && addCosts(7, -3) == 4,
"PBQP cost arithmetic must saturate deterministically");
CostVector Vector(std::vector<Cost>{8, -2, 4});
Context.expect(Vector.minimumIndex() == 1,
"PBQP cost vectors must choose the first stable minimum");
CostMatrix Matrix(2, 3);
Matrix.at(0, 0) = 1;
Matrix.at(0, 1) = 2;
Matrix.at(0, 2) = 3;
Matrix.at(1, 0) = 4;
Matrix.at(1, 1) = 5;
Matrix.at(1, 2) = 6;
const CostMatrix Transposed = Matrix.transpose();
Context.expect(Transposed.rows() == 3 && Transposed.columns() == 2 && Transposed.at(2, 1) == 6 &&
Transposed.at(1, 0) == 2,
"PBQP matrix transposition must preserve orientation");
}
void testGraphValidation(TestContext &Context) {
using namespace rcc::pbqp;
Graph Problem;
auto Empty = Problem.addNode(CostVector(0));
auto First = Problem.addNode(CostVector(std::vector<Cost>{0, 1}), 20);
auto Second = Problem.addNode(CostVector(std::vector<Cost>{2, 0, 3}), 10);
Context.expect(!Empty && First && Second,
"PBQP graphs must reject empty nodes and accept stable nonempty nodes");
if (!First || !Second)
return;
auto Self = Problem.addEdge(*First, *First, CostMatrix(2, 2));
auto WrongShape = Problem.addEdge(*First, *Second, CostMatrix(2, 2));
CostMatrix EdgeCosts(2, 3);
EdgeCosts.at(1, 2) = 7;
auto Edge = Problem.addEdge(*Second, *First, EdgeCosts.transpose(), 99);
auto Duplicate = Problem.addEdge(*First, *Second, CostMatrix(2, 3));
Context.expect(!Self && !WrongShape && Edge && !Duplicate && Problem.verify().has_value(),
"PBQP graph edges must enforce identity, dimensions, orientation, and uniqueness");
if (!Edge)
return;
const rcc::pbqp::Edge *Stored = Problem.edge(*Edge);
Context.expect(Stored != nullptr && Stored->First == *First && Stored->Second == *Second &&
Stored->Costs.rows() == 2 && Stored->Costs.columns() == 3 &&
Stored->Costs.at(1, 2) == 7,
"PBQP graph insertion must normalize reversed edge orientation");
}
void testReductions(TestContext &Context) {
using namespace rcc::pbqp;
DeterministicSolver Solver;
Graph DegreeZero;
auto Only = DegreeZero.addNode(CostVector(std::vector<Cost>{4, 1, 1}), 3);
auto ZeroSolution = Solver.solve(DegreeZero);
Context.expect(Only && ZeroSolution && ZeroSolution->selection(*Only) == 1 &&
ZeroSolution->totalCost() == 1,
"PBQP R0 reduction must select the first minimum-cost option");
Graph DegreeOne;
auto Left = DegreeOne.addNode(CostVector(std::vector<Cost>{3, 0}), 1);
auto Right = DegreeOne.addNode(CostVector(std::vector<Cost>{0, 2}), 2);
CostMatrix Pair(2, 2);
Pair.at(1, 0) = InfiniteCost;
auto PairEdge = DegreeOne.addEdge(*Left, *Right, std::move(Pair));
auto OneSolution = Solver.solve(DegreeOne);
Context.expect(Left && Right && PairEdge && OneSolution && OneSolution->selection(*Left) == 1 &&
OneSolution->selection(*Right) == 1 && OneSolution->totalCost() == 2,
"PBQP R1 reduction must propagate unary costs to its neighbor");
Graph DegreeTwo;
auto A = DegreeTwo.addNode(CostVector(std::vector<Cost>{0, 2}), 1);
auto B = DegreeTwo.addNode(CostVector(std::vector<Cost>{0, 0}), 2);
auto C = DegreeTwo.addNode(CostVector(std::vector<Cost>{2, 0}), 3);
CostMatrix AB(2, 2);
CostMatrix BC(2, 2);
AB.at(0, 1) = 5;
AB.at(1, 0) = 5;
BC.at(0, 1) = 5;
BC.at(1, 0) = 5;
auto ABEdge = DegreeTwo.addEdge(*A, *B, std::move(AB));
auto BCEdge = DegreeTwo.addEdge(*B, *C, std::move(BC));
auto TwoSolution = Solver.solve(DegreeTwo);
Context.expect(A && B && C && ABEdge && BCEdge && TwoSolution &&
TwoSolution->selection(*A) == 0 && TwoSolution->selection(*B) == 0 &&
TwoSolution->selection(*C) == 0 && TwoSolution->totalCost() == 2,
"PBQP R2 reduction must add the induced neighbor edge cost");
}
[[nodiscard]] rcc::Expected<rcc::pbqp::Solution> solveClique() {
using namespace rcc::pbqp;
Graph Problem;
std::vector<NodeID> Nodes;
for (std::uint64_t Index = 0; Index < 4; ++Index) {
auto Node = Problem.addNode(CostVector(std::vector<Cost>{9, 0, 0}), 100 - Index);
if (!Node)
return std::unexpected(Node.error());
Nodes.push_back(*Node);
}
for (std::size_t Left = 0; Left < Nodes.size(); ++Left) {
for (std::size_t Right = Left + 1; Right < Nodes.size(); ++Right) {
CostMatrix Costs(3, 3);
Costs.at(1, 1) = InfiniteCost;
Costs.at(2, 2) = InfiniteCost;
auto Edge = Problem.addEdge(Nodes[Left], Nodes[Right], std::move(Costs),
static_cast<std::uint64_t>(Left * Nodes.size() + Right));
if (!Edge)
return std::unexpected(Edge.error());
}
}
return DeterministicSolver{}.solve(Problem);
}
void testHeuristicAndDeterminism(TestContext &Context) {
auto First = solveClique();
auto Second = solveClique();
Context.expect(First && Second && std::ranges::equal(First->selections(), Second->selections()) &&
First->totalCost() == Second->totalCost(),
"PBQP higher-degree reduction must be deterministic");
if (First) {
Context.expect(First->totalCost() == 18,
"a four-node two-register clique must spill exactly two nodes");
}
rcc::pbqp::Graph Impossible;
auto Node = Impossible.addNode(
rcc::pbqp::CostVector(std::vector<rcc::pbqp::Cost>{rcc::pbqp::InfiniteCost}));
auto Failure = rcc::pbqp::DeterministicSolver{}.solve(Impossible);
Context.expect(Node && !Failure &&
Failure.error().code() == rcc::ErrorCode::RegisterAllocationFailed,
"PBQP solver must diagnose a problem with no finite assignment");
}
} // namespace
int main() {
TestContext Context;
testMath(Context);
testGraphValidation(Context);
testReductions(Context);
testHeuristicAndDeterminism(Context);
return Context.result();
}
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