test/411-optimizing-arith/src/Main.java

/*
 * Copyright (C) 2014 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.
 */

// Note that $opt$ is a marker for the optimizing compiler to ensure
// it does compile the method.

public class Main {

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

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

  public static void main(String[] args) {
    mul();
    neg();
  }

  public static void mul() {
    expectEquals(15, $opt$Mul(5, 3));
    expectEquals(0, $opt$Mul(0, 3));
    expectEquals(0, $opt$Mul(3, 0));
    expectEquals(-3, $opt$Mul(1, -3));
    expectEquals(36, $opt$Mul(-12, -3));
    expectEquals(33, $opt$Mul(1, 3) * 11);
    expectEquals(671088645, $opt$Mul(134217729, 5)); // (2^27 + 1) * 5

    expectEquals(15L, $opt$Mul(5L, 3L));
    expectEquals(0L, $opt$Mul(0L, 3L));
    expectEquals(0L, $opt$Mul(3L, 0L));
    expectEquals(-3L, $opt$Mul(1L, -3L));
    expectEquals(36L, $opt$Mul(-12L, -3L));
    expectEquals(33L, $opt$Mul(1L, 3L) * 11);
    expectEquals(240518168583L, $opt$Mul(34359738369L, 7L)); // (2^35 + 1) * 7

    $opt$InplaceNegOne(1);
  }

  public static void neg() {
    expectEquals(-1, $opt$Neg(1));
    expectEquals(1, $opt$Neg(-1));
    expectEquals(0, $opt$Neg(0));
    expectEquals(51, $opt$Neg(-51));
    expectEquals(-51, $opt$Neg(51));
    expectEquals(2147483647, $opt$Neg(-2147483647));  // (2^31 - 1)
    expectEquals(-2147483647, $opt$Neg(2147483647));  // -(2^31 - 1)
    // From the Java 7 SE Edition specification:
    // http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.15.4
    //
    //   For integer values, negation is the same as subtraction from
    //   zero.  The Java programming language uses two's-complement
    //   representation for integers, and the range of two's-complement
    //   values is not symmetric, so negation of the maximum negative
    //   int or long results in that same maximum negative number.
    //   Overflow occurs in this case, but no exception is thrown.
    //   For all integer values x, -x equals (~x)+1.''
    expectEquals(-2147483648, $opt$Neg(-2147483648)); // -(2^31)
  }

  public static void $opt$InplaceNegOne(int a) {
    a = -a;
    expectEquals(-1, a);
  }

  static int $opt$Mul(int a, int b) {
    return a * b;
  }

  static long $opt$Mul(long a, long b) {
    return a * b;
  }

  static int $opt$Neg(int a){
    return -a;
  }
}