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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 *

 * 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.

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package org.graalvm.compiler.core.test;

import static org.graalvm.compiler.graph.test.matchers.NodeIterableCount.hasCount;

import static org.graalvm.compiler.graph.test.matchers.NodeIterableIsEmpty.isEmpty;

import static org.junit.Assert.assertNotNull;

import static org.junit.Assert.assertThat;

import org.graalvm.compiler.core.common.type.StampFactory;

import org.graalvm.compiler.nodes.LoopBeginNode;

import org.graalvm.compiler.nodes.ParameterNode;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.extended.IntegerSwitchNode;

import org.graalvm.compiler.phases.common.CanonicalizerPhase;

import org.graalvm.compiler.phases.tiers.HighTierContext;

import org.junit.Test;

import jdk.vm.ci.meta.JavaKind;

public class SwitchDyingLoopTest extends GraalCompilerTest {

    @SuppressWarnings("fallthrough")

    public static int snippet(int a, int n) {

        int r = 0;

        loop: for (int i = 0; i < n; i++) {

            int v = (i * 167 + 13) & 0xff;

            switch (v & a) {

                case 0x80:

                    r += 1; // fall through

                case 0x40:

                    r += 2; // fall through

                case 0x20:

                    r += 3;

                    continue;

                case 0x08:

                    r += 5; // fall through

                case 0x04:

                    r += 7; // fall through

                case 0x02:

                    r += 9; // fall through

                default:

                    break loop;

            }

        }

        return r;

    }

    @Test

    public void test() {

        HighTierContext highTierContext = getDefaultHighTierContext();

        StructuredGraph graph = parseEager("snippet", StructuredGraph.AllowAssumptions.YES);

        // there should be 1 loop and 1 switch

        assertThat(graph.getNodes(LoopBeginNode.TYPE), hasCount(1));

        assertThat(graph.getNodes().filter(IntegerSwitchNode.class), hasCount(1));

        canonicalizerPhase.apply(graph, highTierContext);

        // after canonicalization, the loop and switch should still be there

        assertThat(graph.getNodes(LoopBeginNode.TYPE), hasCount(1));

        assertThat(graph.getNodes().filter(IntegerSwitchNode.class), hasCount(1));

        // add stamp to `a` so that paths leading to continue can be trimmed

        ParameterNode parameter = graph.getParameter(0);

        assertNotNull(parameter);

        parameter.setStamp(StampFactory.forInteger(JavaKind.Int, 0, 255, 0, 0xf));

        canonicalizerPhase.apply(graph, highTierContext);

        // the loop should have disappeared and there should still be a switch

        assertThat(graph.getNodes(LoopBeginNode.TYPE), isEmpty());

        assertThat(graph.getNodes().filter(IntegerSwitchNode.class), hasCount(1));

    }

}