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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 import java.util.Arrays;
     18 
     19 //
     20 // Test on array parameters with or without potential aliasing.
     21 //
     22 public class Main {
     23 
     24   //
     25   // Cross-over on parameters with potential aliasing on parameters.
     26   // The arrays a and b may point to the same memory, which (without
     27   // further runtime tests) prevents hoisting the seemingly invariant
     28   // array reference.
     29   //
     30 
     31   /// CHECK-START: void Main.CrossOverLoop1(int[], int[]) licm (before)
     32   /// CHECK-DAG: ArraySet loop:none
     33   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
     34   /// CHECK-DAG: ArraySet loop:{{B\d+}}
     35   //
     36   /// CHECK-START: void Main.CrossOverLoop1(int[], int[]) licm (after)
     37   /// CHECK-DAG: ArraySet loop:none
     38   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
     39   /// CHECK-DAG: ArraySet loop:{{B\d+}}
     40   private static void CrossOverLoop1(int a[], int b[]) {
     41     b[20] = 99;
     42     for (int i = 0; i < a.length; i++) {
     43       a[i] = b[20] - 7;
     44     }
     45   }
     46 
     47   /// CHECK-START: void Main.CrossOverLoop2(float[], float[]) licm (before)
     48   /// CHECK-DAG: ArraySet loop:none
     49   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
     50   /// CHECK-DAG: ArraySet loop:{{B\d+}}
     51   //
     52   /// CHECK-START: void Main.CrossOverLoop2(float[], float[]) licm (after)
     53   /// CHECK-DAG: ArraySet loop:none
     54   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
     55   /// CHECK-DAG: ArraySet loop:{{B\d+}}
     56   private static void CrossOverLoop2(float a[], float b[]) {
     57     b[20] = 99;
     58     for (int i = 0; i < a.length; i++) {
     59       a[i] = b[20] - 7;
     60     }
     61   }
     62 
     63   /// CHECK-START: void Main.CrossOverLoop3(long[], long[]) licm (before)
     64   /// CHECK-DAG: ArraySet loop:none
     65   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
     66   /// CHECK-DAG: ArraySet loop:{{B\d+}}
     67   //
     68   /// CHECK-START: void Main.CrossOverLoop3(long[], long[]) licm (after)
     69   /// CHECK-DAG: ArraySet loop:none
     70   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
     71   /// CHECK-DAG: ArraySet loop:{{B\d+}}
     72   private static void CrossOverLoop3(long a[], long b[]) {
     73     b[20] = 99;
     74     for (int i = 0; i < a.length; i++) {
     75       a[i] = b[20] - 7;
     76     }
     77   }
     78 
     79   /// CHECK-START: void Main.CrossOverLoop4(double[], double[]) licm (before)
     80   /// CHECK-DAG: ArraySet loop:none
     81   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
     82   /// CHECK-DAG: ArraySet loop:{{B\d+}}
     83   //
     84   /// CHECK-START: void Main.CrossOverLoop4(double[], double[]) licm (after)
     85   /// CHECK-DAG: ArraySet loop:none
     86   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
     87   /// CHECK-DAG: ArraySet loop:{{B\d+}}
     88   private static void CrossOverLoop4(double a[], double b[]) {
     89     b[20] = 99;
     90     for (int i = 0; i < a.length; i++) {
     91       a[i] = b[20] - 7;
     92     }
     93   }
     94 
     95   //
     96   // False cross-over on parameters. Parameters have same width (which used to
     97   // cause a false type aliasing in an older version of the compiler), but since
     98   // the types are different cannot be aliased. Thus, the invariant array
     99   // reference can be hoisted.
    100   //
    101 
    102   /// CHECK-START: void Main.FalseCrossOverLoop1(int[], float[]) licm (before)
    103   /// CHECK-DAG: ArraySet loop:none
    104   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    105   /// CHECK-DAG: ArraySet loop:{{B\d+}}
    106   //
    107   /// CHECK-START: void Main.FalseCrossOverLoop1(int[], float[]) licm (after)
    108   /// CHECK-DAG: ArraySet loop:none
    109   /// CHECK-DAG: ArrayGet loop:none
    110   /// CHECK-DAG: ArraySet loop:{{B\d+}}
    111   private static void FalseCrossOverLoop1(int a[], float b[]) {
    112     b[20] = -99;
    113     for (int i = 0; i < a.length; i++) {
    114       a[i] = (int) b[20] - 7;
    115     }
    116   }
    117 
    118   /// CHECK-START: void Main.FalseCrossOverLoop2(float[], int[]) licm (before)
    119   /// CHECK-DAG: ArraySet loop:none
    120   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    121   /// CHECK-DAG: ArraySet loop:{{B\d+}}
    122   //
    123   /// CHECK-START: void Main.FalseCrossOverLoop2(float[], int[]) licm (after)
    124   /// CHECK-DAG: ArraySet loop:none
    125   /// CHECK-DAG: ArrayGet loop:none
    126   /// CHECK-DAG: ArraySet loop:{{B\d+}}
    127   private static void FalseCrossOverLoop2(float a[], int b[]) {
    128     b[20] = -99;
    129     for (int i = 0; i < a.length; i++) {
    130       a[i] = b[20] - 7;
    131     }
    132   }
    133 
    134   /// CHECK-START: void Main.FalseCrossOverLoop3(long[], double[]) licm (before)
    135   /// CHECK-DAG: ArraySet loop:none
    136   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    137   /// CHECK-DAG: ArraySet loop:{{B\d+}}
    138   //
    139   /// CHECK-START: void Main.FalseCrossOverLoop3(long[], double[]) licm (after)
    140   /// CHECK-DAG: ArraySet loop:none
    141   /// CHECK-DAG: ArrayGet loop:none
    142   /// CHECK-DAG: ArraySet loop:{{B\d+}}
    143   private static void FalseCrossOverLoop3(long a[], double b[]) {
    144     b[20] = -99;
    145     for (int i = 0; i < a.length; i++) {
    146       a[i] = (long) b[20] - 7;
    147     }
    148   }
    149 
    150   /// CHECK-START: void Main.FalseCrossOverLoop4(double[], long[]) licm (before)
    151   /// CHECK-DAG: ArraySet loop:none
    152   /// CHECK-DAG: ArrayGet loop:{{B\d+}}
    153   /// CHECK-DAG: ArraySet loop:{{B\d+}}
    154   //
    155   /// CHECK-START: void Main.FalseCrossOverLoop4(double[], long[]) licm (after)
    156   /// CHECK-DAG: ArraySet loop:none
    157   /// CHECK-DAG: ArrayGet loop:none
    158   /// CHECK-DAG: ArraySet loop:{{B\d+}}
    159   private static void FalseCrossOverLoop4(double a[], long b[]) {
    160     b[20] = -99;
    161     for (int i = 0; i < a.length; i++) {
    162       a[i] = b[20] - 7;
    163     }
    164   }
    165 
    166   //
    167   // Main driver and testers.
    168   //
    169 
    170   public static void main(String[] args) {
    171     int[] aI = new int[100];
    172     float[] aF = new float[100];
    173     long[] aJ = new long[100];
    174     double[] aD = new double[100];
    175 
    176     // Type I.
    177     CrossOverLoop1(aI, aI);
    178     for (int i = 0; i < aI.length; i++) {
    179       expectEquals(i <= 20 ? 92 : 85, aI[i]);
    180     }
    181     // Type F.
    182     CrossOverLoop2(aF, aF);
    183     for (int i = 0; i < aF.length; i++) {
    184       expectEquals(i <= 20 ? 92 : 85, aF[i]);
    185     }
    186     // Type J.
    187     CrossOverLoop3(aJ, aJ);
    188     for (int i = 0; i < aJ.length; i++) {
    189       expectEquals(i <= 20 ? 92 : 85, aJ[i]);
    190     }
    191     // Type D.
    192     CrossOverLoop4(aD, aD);
    193     for (int i = 0; i < aD.length; i++) {
    194       expectEquals(i <= 20 ? 92 : 85, aD[i]);
    195     }
    196 
    197     // Type I vs F.
    198     FalseCrossOverLoop1(aI, aF);
    199     for (int i = 0; i < aI.length; i++) {
    200       expectEquals(-106, aI[i]);
    201     }
    202     // Type F vs I.
    203     FalseCrossOverLoop2(aF, aI);
    204     for (int i = 0; i < aF.length; i++) {
    205       expectEquals(-106, aF[i]);
    206     }
    207     // Type J vs D.
    208     FalseCrossOverLoop3(aJ, aD);
    209     for (int i = 0; i < aJ.length; i++) {
    210       expectEquals(-106, aJ[i]);
    211     }
    212     // Type D vs J.
    213     FalseCrossOverLoop4(aD, aJ);
    214     for (int i = 0; i < aD.length; i++) {
    215       expectEquals(-106, aD[i]);
    216     }
    217 
    218     // Real-world example where incorrect type assignment could introduce a bug.
    219     // The library sorting algorithm is heavy on array reads and writes, and
    220     // assigning the wrong J/D type to one of these would introduce errors.
    221     for (int i = 0; i < aD.length; i++) {
    222       aD[i] = aD.length - i - 1;
    223     }
    224     Arrays.sort(aD);
    225     for (int i = 0; i < aD.length; i++) {
    226       expectEquals((double) i, aD[i]);
    227     }
    228 
    229     System.out.println("passed");
    230   }
    231 
    232   private static void expectEquals(int expected, int result) {
    233     if (expected != result) {
    234       throw new Error("Expected: " + expected + ", found: " + result);
    235     }
    236   }
    237 
    238   private static void expectEquals(long expected, long result) {
    239     if (expected != result) {
    240       throw new Error("Expected: " + expected + ", found: " + result);
    241     }
    242   }
    243 
    244   private static void expectEquals(float expected, float result) {
    245     if (expected != result) {
    246       throw new Error("Expected: " + expected + ", found: " + result);
    247     }
    248   }
    249 
    250   private static void expectEquals(double expected, double result) {
    251     if (expected != result) {
    252       throw new Error("Expected: " + expected + ", found: " + result);
    253     }
    254   }
    255 }
    256