1 /*
   2  * Copyright (c) 2012, 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 package org.graalvm.compiler.core.test;
  24 
  25 import org.junit.Test;
  26 
  27 import org.graalvm.compiler.core.common.type.IntegerStamp;
  28 import org.graalvm.compiler.nodes.StructuredGraph;
  29 import org.graalvm.compiler.nodes.StructuredGraph.AllowAssumptions;
  30 import org.graalvm.compiler.phases.common.CanonicalizerPhase;
  31 import org.graalvm.compiler.phases.common.DeadCodeEliminationPhase;
  32 import org.graalvm.compiler.phases.tiers.PhaseContext;
  33 
  34 /**
  35  * This class tests some specific patterns the stamp system should be able to canonicalize away
  36  * using {@link IntegerStamp#upMask()}.
  37  */
  38 public class StampCanonicalizerTest extends GraalCompilerTest {
  39 
  40     public static int andStamp(int a, int b) {
  41         int v = (a & 0xffff00) & (b & 0xff0000f);
  42         return v & 1;
  43     }
  44 
  45     @Test
  46     public void testAnd() {
  47         testZeroReturn("andStamp");
  48     }
  49 
  50     public static int shiftLeftStamp1(int a) {
  51         int v = a << 1;
  52         return v & 1;
  53     }
  54 
  55     public static int shiftLeftStamp2(int a) {
  56         int v = a << 1;
  57         if (a == 17) {
  58             v = a * 4;
  59         }
  60         return v & 1;
  61     }
  62 
  63     @Test
  64     public void testShift() {
  65         testZeroReturn("shiftLeftStamp1");
  66         testZeroReturn("shiftLeftStamp2");
  67     }
  68 
  69     public static int upperBoundShiftStamp1(int a) {
  70         int v = a & 0xffff;
  71         return (v << 4) & 0xff00000;
  72     }
  73 
  74     public static int upperBoundShiftStamp2(int a) {
  75         int v = a & 0xffff;
  76         return (v >> 4) & 0xf000;
  77     }
  78 
  79     @Test
  80     public void testUpperBoundShift() {
  81         testZeroReturn("upperBoundShiftStamp1");
  82         testZeroReturn("upperBoundShiftStamp2");
  83     }
  84 
  85     public static int divStamp1(int[] a) {
  86         int v = a.length / 4;
  87         return v & 0x80000000;
  88     }
  89 
  90     public static int divStamp2(int[] a) {
  91         int v = a.length / 5;
  92         return v & 0x80000000;
  93     }
  94 
  95     @Test
  96     public void testDiv() {
  97         testZeroReturn("divStamp1");
  98         testZeroReturn("divStamp2");
  99     }
 100 
 101     public static int distinctMask(int a, int b) {
 102         int x = a & 0xaaaa;
 103         int y = (b & 0x5555) | 0x1;
 104         return x == y ? 1 : 0;
 105     }
 106 
 107     @Test
 108     public void testDistinctMask() {
 109         testZeroReturn("distinctMask");
 110     }
 111 
 112     private void testZeroReturn(String methodName) {
 113         StructuredGraph graph = parseEager(methodName, AllowAssumptions.YES);
 114         new CanonicalizerPhase().apply(graph, new PhaseContext(getProviders()));
 115         new DeadCodeEliminationPhase().apply(graph);
 116         assertConstantReturn(graph, 0);
 117     }
 118 }