jdk

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/*
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 * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 */
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package compiler.gcbarriers;
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import compiler.lib.ir_framework.*;
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import java.lang.invoke.VarHandle;
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import java.lang.invoke.MethodHandles;
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/**
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 * @test
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 * @summary Test that the expanded size of ZGC barriers is taken into account in
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 *          C2's loop unrolling heuristics so that over-unrolling is avoided.
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 *          The tests use volatile memory accesses to prevent C2 from simply
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 *          optimizing them away.
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 * @library /test/lib /
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 * @requires vm.gc.ZGenerational
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 * @run driver compiler.gcbarriers.TestZGCUnrolling
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 */
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public class TestZGCUnrolling {
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    static class Outer {
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        Object f;
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    }
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    static final VarHandle fVarHandle;
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    static {
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        MethodHandles.Lookup l = MethodHandles.lookup();
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        try {
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            fVarHandle = l.findVarHandle(Outer.class, "f", Object.class);
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        } catch (Exception e) {
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            throw new Error(e);
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        }
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    }
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    public static void main(String[] args) {
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        TestFramework.runWithFlags("-XX:+UseZGC", "-XX:+ZGenerational",
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                                   "-XX:LoopUnrollLimit=24");
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    }
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    @Test
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    @IR(counts = {IRNode.STORE_P, "1"})
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    public static void testNoUnrolling(Outer o, Object o1) {
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        for (int i = 0; i < 64; i++) {
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            fVarHandle.setVolatile(o, o1);
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        }
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    }
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    @Run(test = {"testNoUnrolling"})
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    void run() {
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        testNoUnrolling(new Outer(), new Object());
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    }
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}
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