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.
   */
  
  public class Main {
  
    public static void assertIntEquals(int expected, int result) {
      if (expected != result) {
        throw new Error("Expected: " + expected + ", found: " + result);
      }
    }
  
    public static boolean inlineTrue() {
      return true;
    }
  
    public static boolean inlineFalse() {
      return false;
    }
  
    /// CHECK-START: int Main.testTrueBranch(int, int) dead_code_elimination_final (before)
    /// CHECK-DAG:     <<ArgX:i\d+>>    ParameterValue
    /// CHECK-DAG:     <<ArgY:i\d+>>    ParameterValue
    /// CHECK-DAG:                      If
    /// CHECK-DAG:     <<Add:i\d+>>     Add [<<ArgX>>,<<ArgY>>]
    /// CHECK-DAG:     <<Sub:i\d+>>     Sub [<<ArgX>>,<<ArgY>>]
    /// CHECK-DAG:     <<Phi:i\d+>>     Phi [<<Add>>,<<Sub>>]
    /// CHECK-DAG:                      Return [<<Phi>>]
  
    /// CHECK-START: int Main.testTrueBranch(int, int) dead_code_elimination_final (after)
    /// CHECK-DAG:     <<ArgX:i\d+>>    ParameterValue
    /// CHECK-DAG:     <<ArgY:i\d+>>    ParameterValue
    /// CHECK-DAG:     <<Add:i\d+>>     Add [<<ArgX>>,<<ArgY>>]
    /// CHECK-DAG:                      Return [<<Add>>]
  
    /// CHECK-START: int Main.testTrueBranch(int, int) dead_code_elimination_final (after)
    /// CHECK-NOT:                      If
    /// CHECK-NOT:                      Sub
    /// CHECK-NOT:                      Phi
  
    public static int testTrueBranch(int x, int y) {
      int z;
      if (inlineTrue()) {
        z = x + y;
      } else {
        z = x - y;
        // Prevent HSelect simplification by having a branch with multiple instructions.
        System.nanoTime();
      }
      return z;
    }
  
    /// CHECK-START: int Main.testFalseBranch(int, int) dead_code_elimination_final (before)
    /// CHECK-DAG:     <<ArgX:i\d+>>    ParameterValue
    /// CHECK-DAG:     <<ArgY:i\d+>>    ParameterValue
    /// CHECK-DAG:                      If
    /// CHECK-DAG:     <<Add:i\d+>>     Add [<<ArgX>>,<<ArgY>>]
    /// CHECK-DAG:     <<Sub:i\d+>>     Sub [<<ArgX>>,<<ArgY>>]
    /// CHECK-DAG:     <<Phi:i\d+>>     Phi [<<Add>>,<<Sub>>]
    /// CHECK-DAG:                      Return [<<Phi>>]
  
    /// CHECK-START: int Main.testFalseBranch(int, int) dead_code_elimination_final (after)
    /// CHECK-DAG:     <<ArgX:i\d+>>    ParameterValue
    /// CHECK-DAG:     <<ArgY:i\d+>>    ParameterValue
    /// CHECK-DAG:     <<Sub:i\d+>>     Sub [<<ArgX>>,<<ArgY>>]
    /// CHECK-DAG:                      Return [<<Sub>>]
  
    /// CHECK-START: int Main.testFalseBranch(int, int) dead_code_elimination_final (after)
    /// CHECK-NOT:                      If
    /// CHECK-NOT:                      Add
    /// CHECK-NOT:                      Phi
  
    public static int testFalseBranch(int x, int y) {
      int z;
      if (inlineFalse()) {
        z = x + y;
      } else {
        z = x - y;
        // Prevent HSelect simplification by having a branch with multiple instructions.
        System.nanoTime();
      }
      return z;
    }
  
    /// CHECK-START: int Main.testRemoveLoop(int) dead_code_elimination_final (before)
    /// CHECK:                          Mul
  
    /// CHECK-START: int Main.testRemoveLoop(int) dead_code_elimination_final (after)
    /// CHECK-NOT:                      Mul
  
    public static int testRemoveLoop(int x) {
      if (inlineFalse()) {
        for (int i = 0; i < x; ++i) {
          x *= x;
        }
      }
      return x;
    }
  
    /// CHECK-START: int Main.testInfiniteLoop(int) dead_code_elimination_final (before)
    /// CHECK-DAG:                      Return
    /// CHECK-DAG:                      Exit
  
    /// CHECK-START: int Main.testInfiniteLoop(int) dead_code_elimination_final (after)
    /// CHECK-NOT:                      Return
    /// CHECK-NOT:                      Exit
  
    public static int testInfiniteLoop(int x) {
      while (inlineTrue()) {
        x++;
      }
      return x;
    }
  
    /// CHECK-START: int Main.testDeadLoop(int) dead_code_elimination_final (before)
    /// CHECK-DAG:                      If
    /// CHECK-DAG:                      Add
  
    /// CHECK-START: int Main.testDeadLoop(int) dead_code_elimination_final (after)
    /// CHECK-DAG:     <<Arg:i\d+>>     ParameterValue
    /// CHECK-DAG:                      Return [<<Arg>>]
  
    /// CHECK-START: int Main.testDeadLoop(int) dead_code_elimination_final (after)
    /// CHECK-NOT:                      If
    /// CHECK-NOT:                      Add
  
    public static int testDeadLoop(int x) {
      while (inlineFalse()) {
        x++;
      }
      return x;
    }
  
    /// CHECK-START: int Main.testUpdateLoopInformation(int) dead_code_elimination_final (before)
    /// CHECK-DAG:                      If
    /// CHECK-DAG:                      If
    /// CHECK-DAG:                      Add
  
    /// CHECK-START: int Main.testUpdateLoopInformation(int) dead_code_elimination_final (after)
    /// CHECK-DAG:     <<Arg:i\d+>>     ParameterValue
    /// CHECK-DAG:                      Return [<<Arg>>]
  
    /// CHECK-START: int Main.testUpdateLoopInformation(int) dead_code_elimination_final (after)
    /// CHECK-NOT:                      If
    /// CHECK-NOT:                      Add
  
    public static int testUpdateLoopInformation(int x) {
      // Use of Or in the condition generates a dead loop where not all of its
      // blocks are removed. This forces DCE to update their loop information.
      while (inlineFalse() || !inlineTrue()) {
        x++;
      }
      return x;
    }
  
    /// CHECK-START: int Main.testRemoveSuspendCheck(int, int) dead_code_elimination_final (before)
    /// CHECK:                          SuspendCheck
    /// CHECK:                          SuspendCheck
    /// CHECK:                          SuspendCheck
    /// CHECK-NOT:                      SuspendCheck
  
    /// CHECK-START: int Main.testRemoveSuspendCheck(int, int) dead_code_elimination_final (after)
    /// CHECK:                          SuspendCheck
    /// CHECK:                          SuspendCheck
    /// CHECK-NOT:                      SuspendCheck
  
    public static int testRemoveSuspendCheck(int x, int y) {
      // Inner loop will leave behind the header with its SuspendCheck. DCE must
      // remove it, otherwise the outer loop would end up with two.
      while (y > 0) {
        while (inlineFalse() || !inlineTrue()) {
          x++;
        }
        y--;
      }
      return x;
    }
  
    public static void main(String[] args) {
      assertIntEquals(7, testTrueBranch(4, 3));
      assertIntEquals(1, testFalseBranch(4, 3));
      assertIntEquals(42, testRemoveLoop(42));
      assertIntEquals(23, testUpdateLoopInformation(23));
      assertIntEquals(12, testRemoveSuspendCheck(12, 5));
    }
  }
  