/*
* 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 {

  // Note #1: `javac` flips the conditions of If statements.
  // Note #2: In the optimizing compiler, the first input of Phi is always
  //          the fall-through path, i.e. the false branch.

  public static void assertBoolEquals(boolean expected, boolean result) {
    if (expected != result) {
      throw new Error("Expected: " + expected + ", found: " + result);
    }
  }

  public static void assertIntEquals(int expected, int result) {
    if (expected != result) {
      throw new Error("Expected: " + expected + ", found: " + result);
    }
  }

  /*
   * Elementary test negating a boolean. Verifies that blocks are merged and
   * empty branches removed.
   */

  // CHECK-START: boolean Main.BooleanNot(boolean) boolean_simplifier (before)
  // CHECK-DAG:     [[Param:z\d+]]    ParameterValue
  // CHECK-DAG:     [[Const0:i\d+]]   IntConstant 0
  // CHECK-DAG:     [[Const1:i\d+]]   IntConstant 1
  // CHECK-DAG:                       If [ [[Param]] ]
  // CHECK-DAG:     [[Phi:i\d+]]      Phi [ [[Const1]] [[Const0]] ]
  // CHECK-DAG:                       Return [ [[Phi]] ]

  // CHECK-START: boolean Main.BooleanNot(boolean) boolean_simplifier (before)
  // CHECK:                           Goto
  // CHECK:                           Goto
  // CHECK:                           Goto
  // CHECK-NOT:                       Goto

  // CHECK-START: boolean Main.BooleanNot(boolean) boolean_simplifier (after)
  // CHECK-DAG:     [[Param:z\d+]]    ParameterValue
  // CHECK-DAG:     [[Const0:i\d+]]   IntConstant 0
  // CHECK-DAG:     [[NotParam:z\d+]] BooleanNot [ [[Param]] ]
  // CHECK-DAG:                       Return [ [[NotParam]] ]

  // CHECK-START: boolean Main.BooleanNot(boolean) boolean_simplifier (after)
  // CHECK-NOT:                       If
  // CHECK-NOT:                       Phi

  // CHECK-START: boolean Main.BooleanNot(boolean) boolean_simplifier (after)
  // CHECK:                           Goto
  // CHECK-NOT:                       Goto

  public static boolean BooleanNot(boolean x) {
    return !x;
  }

  /*
   * Program which only delegates the condition, i.e. returns 1 when True
   * and 0 when False.
   */

  // CHECK-START: boolean Main.GreaterThan(int, int) boolean_simplifier (before)
  // CHECK-DAG:     [[ParamX:i\d+]]   ParameterValue
  // CHECK-DAG:     [[ParamY:i\d+]]   ParameterValue
  // CHECK-DAG:     [[Const0:i\d+]]   IntConstant 0
  // CHECK-DAG:     [[Const1:i\d+]]   IntConstant 1
  // CHECK-DAG:     [[Cond:z\d+]]     GreaterThan [ [[ParamX]] [[ParamY]] ]
  // CHECK-DAG:                       If [ [[Cond]] ]
  // CHECK-DAG:     [[Phi:i\d+]]      Phi [ [[Const0]] [[Const1]] ]
  // CHECK-DAG:                       Return [ [[Phi]] ]

  // CHECK-START: boolean Main.GreaterThan(int, int) boolean_simplifier (after)
  // CHECK-DAG:     [[ParamX:i\d+]]   ParameterValue
  // CHECK-DAG:     [[ParamY:i\d+]]   ParameterValue
  // CHECK-DAG:     [[Const0:i\d+]]   IntConstant 0
  // CHECK-DAG:     [[Const1:i\d+]]   IntConstant 1
  // CHECK-DAG:     [[Cond:z\d+]]     GreaterThan [ [[ParamX]] [[ParamY]] ]
  // CHECK-DAG:                       Return [ [[Cond]] ]

  public static boolean GreaterThan(int x, int y) {
    return (x <= y) ? false : true;
  }

  /*
   * Program which negates a condition, i.e. returns 0 when True
   * and 1 when False.
   */

  // CHECK-START: boolean Main.LessThan(int, int) boolean_simplifier (before)
  // CHECK-DAG:     [[ParamX:i\d+]]   ParameterValue
  // CHECK-DAG:     [[ParamY:i\d+]]   ParameterValue
  // CHECK-DAG:     [[Const0:i\d+]]   IntConstant 0
  // CHECK-DAG:     [[Const1:i\d+]]   IntConstant 1
  // CHECK-DAG:     [[Cond:z\d+]]     GreaterThanOrEqual [ [[ParamX]] [[ParamY]] ]
  // CHECK-DAG:                       If [ [[Cond]] ]
  // CHECK-DAG:     [[Phi:i\d+]]      Phi [ [[Const1]] [[Const0]] ]
  // CHECK-DAG:                       Return [ [[Phi]] ]

  // CHECK-START: boolean Main.LessThan(int, int) boolean_simplifier (after)
  // CHECK-DAG:     [[ParamX:i\d+]]   ParameterValue
  // CHECK-DAG:     [[ParamY:i\d+]]   ParameterValue
  // CHECK-DAG:     [[Const0:i\d+]]   IntConstant 0
  // CHECK-DAG:     [[Const1:i\d+]]   IntConstant 1
  // CHECK-DAG:     [[Cond:z\d+]]     LessThan [ [[ParamX]] [[ParamY]] ]
  // CHECK-DAG:                       Return [ [[Cond]] ]

  // CHECK-START: boolean Main.LessThan(int, int) boolean_simplifier (after)
  // CHECK-NOT:                       GreaterThanOrEqual

  public static boolean LessThan(int x, int y) {
    return (x < y) ? true : false;
  }

  /*
   * Program which further uses negated conditions.
   * Note that Phis are discovered retrospectively.
   */

  // CHECK-START: boolean Main.ValuesOrdered(int, int, int) boolean_simplifier (before)
  // CHECK-DAG:     [[ParamX:i\d+]]   ParameterValue
  // CHECK-DAG:     [[ParamY:i\d+]]   ParameterValue
  // CHECK-DAG:     [[ParamZ:i\d+]]   ParameterValue
  // CHECK-DAG:     [[Const0:i\d+]]   IntConstant 0
  // CHECK-DAG:     [[Const1:i\d+]]   IntConstant 1
  // CHECK-DAG:     [[CondXY:z\d+]]   GreaterThan [ [[ParamX]] [[ParamY]] ]
  // CHECK-DAG:                       If [ [[CondXY]] ]
  // CHECK-DAG:     [[CondYZ:z\d+]]   GreaterThan [ [[ParamY]] [[ParamZ]] ]
  // CHECK-DAG:                       If [ [[CondYZ]] ]
  // CHECK-DAG:     [[CondXYZ:z\d+]]  NotEqual [ [[PhiXY:i\d+]] [[PhiYZ:i\d+]] ]
  // CHECK-DAG:                       If [ [[CondXYZ]] ]
  // CHECK-DAG:                       Return [ [[PhiXYZ:i\d+]] ]
  // CHECK-DAG:     [[PhiXY]]         Phi [ [[Const1]] [[Const0]] ]
  // CHECK-DAG:     [[PhiYZ]]         Phi [ [[Const1]] [[Const0]] ]
  // CHECK-DAG:     [[PhiXYZ]]        Phi [ [[Const1]] [[Const0]] ]

  // CHECK-START: boolean Main.ValuesOrdered(int, int, int) boolean_simplifier (after)
  // CHECK-DAG:     [[ParamX:i\d+]]   ParameterValue
  // CHECK-DAG:     [[ParamY:i\d+]]   ParameterValue
  // CHECK-DAG:     [[ParamZ:i\d+]]   ParameterValue
  // CHECK-DAG:     [[CmpXY:z\d+]]    LessThanOrEqual [ [[ParamX]] [[ParamY]] ]
  // CHECK-DAG:     [[CmpYZ:z\d+]]    LessThanOrEqual [ [[ParamY]] [[ParamZ]] ]
  // CHECK-DAG:     [[CmpXYZ:z\d+]]   Equal [ [[CmpXY]] [[CmpYZ]] ]
  // CHECK-DAG:                       Return [ [[CmpXYZ]] ]

  public static boolean ValuesOrdered(int x, int y, int z) {
    return (x <= y) == (y <= z);
  }

  // CHECK-START: int Main.NegatedCondition(boolean) boolean_simplifier (before)
  // CHECK-DAG:     [[Param:z\d+]]    ParameterValue
  // CHECK-DAG:     [[Const42:i\d+]]  IntConstant 42
  // CHECK-DAG:     [[Const43:i\d+]]  IntConstant 43
  // CHECK-DAG:     [[NotParam:z\d+]] BooleanNot [ [[Param]] ]
  // CHECK-DAG:                       If [ [[NotParam]] ]
  // CHECK-DAG:     [[Phi:i\d+]]      Phi [ [[Const42]] [[Const43]] ]
  // CHECK-DAG:                       Return [ [[Phi]] ]

  // CHECK-START: int Main.NegatedCondition(boolean) boolean_simplifier (after)
  // CHECK-DAG:     [[Param:z\d+]]    ParameterValue
  // CHECK-DAG:     [[Const42:i\d+]]  IntConstant 42
  // CHECK-DAG:     [[Const43:i\d+]]  IntConstant 43
  // CHECK-DAG:                       If [ [[Param]] ]
  // CHECK-DAG:     [[Phi:i\d+]]      Phi [ [[Const42]] [[Const43]] ]
  // CHECK-DAG:                       Return [ [[Phi]] ]

  // Note: The fact that branches are swapped is verified by running the test.

  // CHECK-START: int Main.NegatedCondition(boolean) boolean_simplifier (after)
  // CHECK-NOT:                       BooleanNot

  public static int NegatedCondition(boolean x) {
    if (x != false) {
      return 42;
    } else {
      return 43;
    }
  }

  public static void main(String[] args) {
    assertBoolEquals(false, BooleanNot(true));
    assertBoolEquals(true, BooleanNot(false));
    assertBoolEquals(true, GreaterThan(10, 5));
    assertBoolEquals(false, GreaterThan(10, 10));
    assertBoolEquals(false, GreaterThan(5, 10));
    assertBoolEquals(true, LessThan(5, 10));
    assertBoolEquals(false, LessThan(10, 10));
    assertBoolEquals(false, LessThan(10, 5));
    assertBoolEquals(true, ValuesOrdered(1, 3, 5));
    assertBoolEquals(true, ValuesOrdered(5, 3, 1));
    assertBoolEquals(false, ValuesOrdered(1, 3, 2));
    assertBoolEquals(false, ValuesOrdered(2, 3, 1));
    assertBoolEquals(true, ValuesOrdered(3, 3, 3));
    assertBoolEquals(true, ValuesOrdered(3, 3, 5));
    assertBoolEquals(false, ValuesOrdered(5, 5, 3));
    assertIntEquals(42, NegatedCondition(true));
    assertIntEquals(43, NegatedCondition(false));
  }
}