mirror of
https://github.com/openjdk/jdk.git
synced 2026-01-28 12:09:14 +00:00
92 lines
3.1 KiB
Java
92 lines
3.1 KiB
Java
/*
|
|
* Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
|
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
*
|
|
* This code is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 only, as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This code is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* version 2 for more details (a copy is included in the LICENSE file that
|
|
* accompanied this code).
|
|
*
|
|
* You should have received a copy of the GNU General Public License version
|
|
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
|
|
* or visit www.oracle.com if you need additional information or have any
|
|
* questions.
|
|
*/
|
|
|
|
/*
|
|
* @test
|
|
* @bug 8348572
|
|
* @summary Tests where new irreducible loop is introduced by split_if.
|
|
*
|
|
* @run driver compiler.loopopts.TestSplitIfNewIrreducibleLoop
|
|
*
|
|
* @run main/othervm -Xcomp -XX:PerMethodTrapLimit=0
|
|
* -XX:CompileCommand=compileonly,compiler.loopopts.TestSplitIfNewIrreducibleLoop::test
|
|
* compiler.loopopts.TestSplitIfNewIrreducibleLoop
|
|
*/
|
|
|
|
package compiler.loopopts;
|
|
|
|
public class TestSplitIfNewIrreducibleLoop {
|
|
|
|
static class A {
|
|
public A parent;
|
|
}
|
|
|
|
static class B extends A {}
|
|
|
|
public static void main(String[] args) {
|
|
// Instantiate one each: classes are loaded.
|
|
A a = new A();
|
|
B b = new B();
|
|
test(b);
|
|
}
|
|
|
|
static int test(A parent) {
|
|
do {
|
|
if (parent instanceof B b) { return 1; }
|
|
if (parent != null) { parent = parent.parent; }
|
|
if (parent == null) { return 0; }
|
|
} while (true);
|
|
}
|
|
|
|
// Before split_if it looks like this (the instanceof check has already been partial peeled):
|
|
//
|
|
// if (parent instanceof B b) { return 1; }
|
|
// do {
|
|
// if (parent != null) { parent = parent.parent; }
|
|
// if (parent == null) { return 0; }
|
|
// if (parent instanceof B b) { return 1; }
|
|
// } while (true);
|
|
//
|
|
//
|
|
// Now, we want to split_if the first if in the loop body, like this:
|
|
//
|
|
// if (parent instanceof B b) { return 1; }
|
|
// if (parent != null) { goto LOOP2; } else { goto LOOP1; }
|
|
// do {
|
|
// :LOOP1
|
|
// parent = parent.parent;
|
|
// :LOOP2
|
|
// if (parent == null) { return 0; }
|
|
// if (parent instanceof B b) { return 1; }
|
|
// if (parent != null) { goto LOOP2; } else { goto LOOP1; }
|
|
// } while (true);
|
|
//
|
|
// As the comment in ifnode.cpp / split_if says: we know that on the backedge
|
|
// "parent" cannot be null, and so we would be able to split the if through
|
|
// the region, and on the backedge it would constant fold away, and we would
|
|
// only have to check the split if in the loop entry.
|
|
//
|
|
// Problem: we have introduced an irreducible loop!
|
|
}
|
|
|