import java.util.*;

/**
 * CWE-407 unit tests for LLVM defects (new: llvm-0006).
 *
 * llvm-0006: PartialInlining IsSingleExit — is_contained(BlockList, ...) O(N²)
 *
 * (llvm-0001 through llvm-0005 have separate unit tests or are covered
 *  by LlvmAliasSetTest.java, LlvmDomConditionCacheTest.java, etc.)
 */
public class LlvmTest {

    // ---------------------------------------------------------------
    // llvm-0006: PartialInlining IsSingleExit BlockList membership
    // is_contained(BlockList, Succ) inside nested for loops → O(N² × S)
    // ---------------------------------------------------------------

    /** Defective: linear scan for block list membership */
    static int isSingleExitDefective(int blockCount) {
        List<Integer> blockList = new ArrayList<>();
        for (int i = 0; i < blockCount; i++) blockList.add(i);
        int ops = 0;

        for (int block : blockList) {
            // Each block has ~2 successors
            int[] successors = { block + 1, block + blockCount / 3 };
            for (int succ : successors) {
                // Linear scan: is_contained(BlockList, Succ)
                for (int b : blockList) {
                    ops++;
                    if (b == succ) break;
                }
            }
        }
        return ops;
    }

    /** Fixed: SmallPtrSet for block list membership */
    static int isSingleExitFixed(int blockCount) {
        Set<Integer> blockSet = new HashSet<>();
        for (int i = 0; i < blockCount; i++) blockSet.add(i);
        int ops = 0;

        for (int block = 0; block < blockCount; block++) {
            int[] successors = { block + 1, block + blockCount / 3 };
            for (int succ : successors) {
                ops++; // O(1) hash lookup
                blockSet.contains(succ);
            }
        }
        return ops;
    }

    // ---------------------------------------------------------------
    // Test runner
    // ---------------------------------------------------------------

    static void check(String name, boolean cond) {
        System.out.println((cond ? "PASS" : "FAIL") + " " + name);
        if (!cond) System.exit(1);
    }

    public static void main(String[] args) {
        // llvm-0006: PartialInlining IsSingleExit
        {
            int N = 500;
            int defectOps = isSingleExitDefective(N);
            int fixedOps  = isSingleExitFixed(N);
            double ratio  = (double) defectOps / fixedOps;
            System.out.printf("llvm-0006: defect=%d fixed=%d ratio=%.1fx%n", defectOps, fixedOps, ratio);
            check("llvm-0006-quadratic", defectOps > fixedOps * 10);
            check("llvm-0006-fixed-linear", fixedOps <= N * 3);
        }

        System.out.println("ALL PASS");
    }
}