content: /*
   * Copyright (C) 2015 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  import java.util.Arrays;
  
  //
  // Test on array parameters with or without potential aliasing.
  //
  public class Main {
  
    //
    // Cross-over on parameters with potential aliasing on parameters.
    // The arrays a and b may point to the same memory, which (without
    // further runtime tests) prevents hoisting the seemingly invariant
    // array reference.
    //
  
    /// CHECK-START: void Main.CrossOverLoop1(int[], int[]) licm (before)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    //
    /// CHECK-START: void Main.CrossOverLoop1(int[], int[]) licm (after)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    private static void CrossOverLoop1(int a[], int b[]) {
      b[20] = 99;
      for (int i = 0; i < a.length; i++) {
        a[i] = b[20] - 7;
      }
    }
  
    /// CHECK-START: void Main.CrossOverLoop2(float[], float[]) licm (before)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    //
    /// CHECK-START: void Main.CrossOverLoop2(float[], float[]) licm (after)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    private static void CrossOverLoop2(float a[], float b[]) {
      b[20] = 99;
      for (int i = 0; i < a.length; i++) {
        a[i] = b[20] - 7;
      }
    }
  
    /// CHECK-START: void Main.CrossOverLoop3(long[], long[]) licm (before)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    //
    /// CHECK-START: void Main.CrossOverLoop3(long[], long[]) licm (after)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    private static void CrossOverLoop3(long a[], long b[]) {
      b[20] = 99;
      for (int i = 0; i < a.length; i++) {
        a[i] = b[20] - 7;
      }
    }
  
    /// CHECK-START: void Main.CrossOverLoop4(double[], double[]) licm (before)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    //
    /// CHECK-START: void Main.CrossOverLoop4(double[], double[]) licm (after)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    private static void CrossOverLoop4(double a[], double b[]) {
      b[20] = 99;
      for (int i = 0; i < a.length; i++) {
        a[i] = b[20] - 7;
      }
    }
  
    //
    // False cross-over on parameters. Parameters have same width (which used to
    // cause a false type aliasing in an older version of the compiler), but since
    // the types are different cannot be aliased. Thus, the invariant array
    // reference can be hoisted.
    //
  
    /// CHECK-START: void Main.FalseCrossOverLoop1(int[], float[]) licm (before)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    //
    /// CHECK-START: void Main.FalseCrossOverLoop1(int[], float[]) licm (after)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:none
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    private static void FalseCrossOverLoop1(int a[], float b[]) {
      b[20] = -99;
      for (int i = 0; i < a.length; i++) {
        a[i] = (int) b[20] - 7;
      }
    }
  
    /// CHECK-START: void Main.FalseCrossOverLoop2(float[], int[]) licm (before)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    //
    /// CHECK-START: void Main.FalseCrossOverLoop2(float[], int[]) licm (after)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:none
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    private static void FalseCrossOverLoop2(float a[], int b[]) {
      b[20] = -99;
      for (int i = 0; i < a.length; i++) {
        a[i] = b[20] - 7;
      }
    }
  
    /// CHECK-START: void Main.FalseCrossOverLoop3(long[], double[]) licm (before)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    //
    /// CHECK-START: void Main.FalseCrossOverLoop3(long[], double[]) licm (after)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:none
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    private static void FalseCrossOverLoop3(long a[], double b[]) {
      b[20] = -99;
      for (int i = 0; i < a.length; i++) {
        a[i] = (long) b[20] - 7;
      }
    }
  
    /// CHECK-START: void Main.FalseCrossOverLoop4(double[], long[]) licm (before)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    //
    /// CHECK-START: void Main.FalseCrossOverLoop4(double[], long[]) licm (after)
    /// CHECK-DAG: ArraySet loop:none
    /// CHECK-DAG: ArrayGet loop:none
    /// CHECK-DAG: ArraySet loop:{{B\d+}}
    private static void FalseCrossOverLoop4(double a[], long b[]) {
      b[20] = -99;
      for (int i = 0; i < a.length; i++) {
        a[i] = b[20] - 7;
      }
    }
  
    //
    // Main driver and testers.
    //
  
    public static void main(String[] args) {
      int[] aI = new int[100];
      float[] aF = new float[100];
      long[] aJ = new long[100];
      double[] aD = new double[100];
  
      // Type I.
      CrossOverLoop1(aI, aI);
      for (int i = 0; i < aI.length; i++) {
        expectEquals(i <= 20 ? 92 : 85, aI[i]);
      }
      // Type F.
      CrossOverLoop2(aF, aF);
      for (int i = 0; i < aF.length; i++) {
        expectEquals(i <= 20 ? 92 : 85, aF[i]);
      }
      // Type J.
      CrossOverLoop3(aJ, aJ);
      for (int i = 0; i < aJ.length; i++) {
        expectEquals(i <= 20 ? 92 : 85, aJ[i]);
      }
      // Type D.
      CrossOverLoop4(aD, aD);
      for (int i = 0; i < aD.length; i++) {
        expectEquals(i <= 20 ? 92 : 85, aD[i]);
      }
  
      // Type I vs F.
      FalseCrossOverLoop1(aI, aF);
      for (int i = 0; i < aI.length; i++) {
        expectEquals(-106, aI[i]);
      }
      // Type F vs I.
      FalseCrossOverLoop2(aF, aI);
      for (int i = 0; i < aF.length; i++) {
        expectEquals(-106, aF[i]);
      }
      // Type J vs D.
      FalseCrossOverLoop3(aJ, aD);
      for (int i = 0; i < aJ.length; i++) {
        expectEquals(-106, aJ[i]);
      }
      // Type D vs J.
      FalseCrossOverLoop4(aD, aJ);
      for (int i = 0; i < aD.length; i++) {
        expectEquals(-106, aD[i]);
      }
  
      // Real-world example where incorrect type assignment could introduce a bug.
      // The library sorting algorithm is heavy on array reads and writes, and
      // assigning the wrong J/D type to one of these would introduce errors.
      for (int i = 0; i < aD.length; i++) {
        aD[i] = aD.length - i - 1;
      }
      Arrays.sort(aD);
      for (int i = 0; i < aD.length; i++) {
        expectEquals((double) i, aD[i]);
      }
  
      System.out.println("passed");
    }
  
    private static void expectEquals(int expected, int result) {
      if (expected != result) {
        throw new Error("Expected: " + expected + ", found: " + result);
      }
    }
  
    private static void expectEquals(long expected, long result) {
      if (expected != result) {
        throw new Error("Expected: " + expected + ", found: " + result);
      }
    }
  
    private static void expectEquals(float expected, float result) {
      if (expected != result) {
        throw new Error("Expected: " + expected + ", found: " + result);
      }
    }
  
    private static void expectEquals(double expected, double result) {
      if (expected != result) {
        throw new Error("Expected: " + expected + ", found: " + result);
      }
    }
  }
  