/******************************************************************************
* Copyright (c) 2009 - 2015 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*****************************************************************************/
/**
*
*/
package data.causality;
/**
* Causality test case 1 from
* http://www.cs.umd.edu/~pugh/java/memoryModel/CausalityTestCases.html
*
* <pre>
* Initially, x = y = 0
*
* Thread 1
* r1 = x
* if r1 >= 0
* y = 1
*
* Thread 2
* r2 = y
* x = r2
*
* Behavior in question: r1 == r2 == 1
*
* Decision: Allowed, since interthread compiler analysis could determine that
* x and y are always non-negative, allowing simplification of r1 >= 0
* to true, and allowing write y = 1 to be moved early.
* </pre>
*
* @author etorlak
*/
public final class Test01 {
static int x = 0, y = 0;
public static final void thread1() {
final int r1 = x;
if (r1 >= 0)
y = 1;
assert r1==1;
}
public static final void thread2() {
final int r2 = y;
x = r2;
assert r2==1;
}
}