1 /*
   2  * Copyright (c) 2014, 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  * @test
  26  * @bug 8048170
  27  * @summary Following range check smearing, range check cannot be replaced by dominating identical test.
  28  * @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement TestRangeCheckSmearingLoopOpts
  29  *
  30  */
  31 public class TestRangeCheckSmearingLoopOpts {
  32 
  33     static int dummy;
  34 
  35     static int m1(int[] array, int i) {
  36         for (;;) {
  37             for (;;) {
  38                 if (array[i] < 0) { // range check (i+0) dominates equivalent check below
  39                     break;
  40                 }
  41                 i++;
  42             }
  43 
  44             // A control flow that stops IfNode::up_one_dom()
  45             if ((i % 2)== 0) {
  46                 if ((array[i] % 2) == 0) {
  47                     dummy = i;
  48                 }
  49             }
  50 
  51             // IfNode::Ideal will rewrite some range checks if Compile::allow_range_check_smearing
  52             if (array[i-1] == 9) {    // range check (i-1) unchanged
  53                 int res = array[i-3]; // range check (i-3) unchanged
  54                 res += array[i];      // range check (i+0) unchanged
  55                 res += array[i-2];    // removed redundant range check
  56                 // the previous access might be hoisted by
  57                 // PhaseIdealLoop::split_if_with_blocks_post because
  58                 // it appears to have the same guard, but it also
  59                 // depends on the previous guards
  60                 return res;
  61             }
  62             i++;
  63         }
  64     }
  65 
  66     static public void main(String[] args) {
  67         int[] array = { 0, 1, 2, -3, 4, 5, -2, 7, 8, 9, -1 };
  68         for (int i = 0; i < 20000; i++) {
  69             m1(array, 0);
  70         }
  71         array[0] = -1;
  72         try {
  73             m1(array, 0);
  74         } catch(ArrayIndexOutOfBoundsException aioobe) {}
  75     }
  76 }