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package compiler.c2.irTests.igvn;

import compiler.lib.ir_framework.*;

/*
 * @test
 * @bug 8310524
 * @requires vm.bits == 64
 * @summary Test that IGVN optimizes away one of two identical LoadNs.
 * @library /test/lib /
 * @run driver compiler.c2.irTests.igvn.TestLoadNIdeal
 */

public class TestLoadNIdeal {

    public static void main(String[] args) {
        // Ensure that we run with compressed oops
        TestFramework.runWithFlags("-XX:+UseCompressedOops");
    }

    static class A { int x; }

    @DontInline
    void dummy(A p[]) { }

    @Test
    @IR(applyIf = { "UseCompressedOops", "true" }, counts = { IRNode.LOAD_N, "1" })
    int test() {
        A p[] = new A[1];
        p[0] = new A();

        // The dummy method is not inlined => Escape analysis
        // cannot ensure that p[0] is unmodified after the call.
        dummy(p);

        // We should only need to load p[0] once here. Storing A within an
        // array adds range checks for the first load and ensures the second
        // load is not optimized already at bytecode parsing.
        return p[0].x + p[0].x;
    }
}