1 /*
   2  * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 
  25 package org.graalvm.compiler.core.test;
  26 
  27 import static org.graalvm.compiler.graph.test.matchers.NodeIterableCount.hasCount;
  28 import static org.graalvm.compiler.graph.test.matchers.NodeIterableIsEmpty.isEmpty;
  29 import static org.junit.Assert.assertNotNull;
  30 import static org.junit.Assert.assertThat;
  31 
  32 import org.graalvm.compiler.core.common.type.StampFactory;
  33 import org.graalvm.compiler.nodes.LoopBeginNode;
  34 import org.graalvm.compiler.nodes.ParameterNode;
  35 import org.graalvm.compiler.nodes.StructuredGraph;
  36 import org.graalvm.compiler.nodes.extended.IntegerSwitchNode;
  37 import org.graalvm.compiler.phases.common.CanonicalizerPhase;
  38 import org.graalvm.compiler.phases.tiers.HighTierContext;
  39 import org.junit.Test;
  40 
  41 import jdk.vm.ci.meta.JavaKind;
  42 
  43 public class SwitchDyingLoopTest extends GraalCompilerTest {
  44 
  45     @SuppressWarnings("fallthrough")
  46     public static int snippet(int a, int n) {
  47         int r = 0;
  48         loop: for (int i = 0; i < n; i++) {
  49             int v = (i * 167 + 13) & 0xff;
  50             switch (v & a) {
  51                 case 0x80:
  52                     r += 1; // fall through
  53                 case 0x40:
  54                     r += 2; // fall through
  55                 case 0x20:
  56                     r += 3;
  57                     continue;
  58                 case 0x08:
  59                     r += 5; // fall through
  60                 case 0x04:
  61                     r += 7; // fall through
  62                 case 0x02:
  63                     r += 9; // fall through
  64                 default:
  65                     break loop;
  66             }
  67         }
  68         return r;
  69     }
  70 
  71     @Test
  72     public void test() {
  73         CanonicalizerPhase canonicalizerPhase = new CanonicalizerPhase();
  74         HighTierContext highTierContext = getDefaultHighTierContext();
  75         StructuredGraph graph = parseEager("snippet", StructuredGraph.AllowAssumptions.YES);
  76         // there should be 1 loop and 1 switch
  77         assertThat(graph.getNodes(LoopBeginNode.TYPE), hasCount(1));
  78         assertThat(graph.getNodes().filter(IntegerSwitchNode.class), hasCount(1));
  79         canonicalizerPhase.apply(graph, highTierContext);
  80         // after canonicalization, the loop and switch should still be there
  81         assertThat(graph.getNodes(LoopBeginNode.TYPE), hasCount(1));
  82         assertThat(graph.getNodes().filter(IntegerSwitchNode.class), hasCount(1));
  83         // add stamp to `a` so that paths leading to continue can be trimmed
  84         ParameterNode parameter = graph.getParameter(0);
  85         assertNotNull(parameter);
  86         parameter.setStamp(StampFactory.forInteger(JavaKind.Int, 0, 255, 0, 0xf));
  87         canonicalizerPhase.apply(graph, highTierContext);
  88         // the loop should have disappeared and there should still be a switch
  89         assertThat(graph.getNodes(LoopBeginNode.TYPE), isEmpty());
  90         assertThat(graph.getNodes().filter(IntegerSwitchNode.class), hasCount(1));
  91     }
  92 }