content: /*
   * Copyright (C) 2016 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.
   */
  
  //
  // Test on loop unrolling. Removes loop control overhead (including suspend
  // checks) and exposes more opportunities for constant folding.
  //
  public class Main {
  
    static int sA = 0;
  
    /// CHECK-START: void Main.unroll() loop_optimization (before)
    /// CHECK-DAG: Phi            loop:<<Loop:B\d+>>
    /// CHECK-DAG: StaticFieldSet loop:<<Loop>>
    //
    /// CHECK-START: void Main.unroll() loop_optimization (after)
    /// CHECK-DAG: StaticFieldSet loop:none
    //
    /// CHECK-START: void Main.unroll() instruction_simplifier$after_bce (after)
    /// CHECK-DAG: <<Int:i\d+>> IntConstant    68                  loop:none
    /// CHECK-DAG:              StaticFieldSet [{{l\d+}},<<Int>>]  loop:none
    //
    /// CHECK-START: void Main.unroll() loop_optimization (after)
    /// CHECK-NOT: Phi
    public static void unroll() {
      for (int i = 4; i < 5; i++) {
        sA = 17 * i;
      }
    }
  
    /// CHECK-START: int Main.unrollLV() loop_optimization (before)
    /// CHECK-DAG: <<Phi:i\d+>> Phi              loop:<<Loop:B\d+>>
    /// CHECK-DAG:              StaticFieldSet   loop:<<Loop>>
    /// CHECK-DAG:              Return [<<Phi>>] loop:none
    //
    /// CHECK-START: int Main.unrollLV() loop_optimization (after)
    /// CHECK-DAG: StaticFieldSet loop:none
    //
    /// CHECK-START: int Main.unrollLV() instruction_simplifier$after_bce (after)
    /// CHECK-DAG: <<Int1:i\d+>> IntConstant    187                 loop:none
    /// CHECK-DAG: <<Int2:i\d+>> IntConstant    12                  loop:none
    /// CHECK-DAG:               StaticFieldSet [{{l\d+}},<<Int1>>] loop:none
    /// CHECK-DAG:               Return [<<Int2>>]                  loop:none
    //
    /// CHECK-START: int Main.unrollLV() loop_optimization (after)
    /// CHECK-NOT: Phi
    public static int unrollLV() {
      int i;
      for (i = 11; i < 12; i++) {
        sA = 17 * i;
      }
      return i;
    }
  
    /// CHECK-START: void Main.unrollNest() loop_optimization (before)
    /// CHECK-DAG:               SuspendCheck    loop:none
    /// CHECK-DAG: <<Phi1:i\d+>> Phi             loop:<<Loop1:B\d+>> outer_loop:none
    /// CHECK-DAG:               SuspendCheck    loop:<<Loop1>>      outer_loop:none
    /// CHECK-DAG: <<Phi2:i\d+>> Phi             loop:<<Loop2:B\d+>> outer_loop:<<Loop1>>
    /// CHECK-DAG:               SuspendCheck    loop:<<Loop2>>      outer_loop:<<Loop1>>
    /// CHECK-DAG: <<Phi3:i\d+>> Phi             loop:<<Loop3:B\d+>> outer_loop:<<Loop2>>
    /// CHECK-DAG:               SuspendCheck    loop:<<Loop3>>      outer_loop:<<Loop2>>
    /// CHECK-DAG:               StaticFieldSet  loop:<<Loop3>>      outer_loop:<<Loop2>>
    //
    /// CHECK-START: void Main.unrollNest() loop_optimization (after)
    /// CHECK-DAG: StaticFieldSet loop:none
    /// CHECK-DAG: SuspendCheck   loop:none
    /// CHECK-NOT: SuspendCheck
    //
    /// CHECK-START: void Main.unrollNest() instruction_simplifier$after_bce (after)
    /// CHECK-DAG: <<Int:i\d+>> IntConstant    6                   loop:none
    /// CHECK-DAG:              StaticFieldSet [{{l\d+}},<<Int>>]  loop:none
    //
    /// CHECK-START: void Main.unrollNest() loop_optimization (after)
    /// CHECK-NOT: Phi
    public static void unrollNest() {
      // Unrolling each loop in turn ultimately removes the complete nest!
      for (int i = 4; i < 5; i++) {
        for (int j = 5; j < 6; j++) {
          for (int k = 6; k < 7; k++) {
            sA = k;
          }
        }
      }
    }
  
    //
    // Verifier.
    //
  
    public static void main(String[] args) {
      unroll();
      expectEquals(68, sA);
      expectEquals(12, unrollLV());
      expectEquals(187, sA);
      unrollNest();
      expectEquals(6, sA);
      System.out.println("passed");
    }
  
    private static void expectEquals(int expected, int result) {
      if (expected != result) {
        throw new Error("Expected: " + expected + ", found: " + result);
      }
    }
  }
  