# HG changeset patch # User iveresov # Date 1424209599 0 # Node ID 9ce801dd67c6fca26210822c11c32583f389655a # Parent 74100114a95a485303e82ab009dfc7d559545aa6# Parent 79c30f6c2125fe7d7e0ec06dca31c5e58bc9c807 Merge diff -r 74100114a95a -r 9ce801dd67c6 hotspot/src/share/vm/opto/loopnode.cpp --- a/hotspot/src/share/vm/opto/loopnode.cpp Tue Feb 17 13:54:53 2015 -0500 +++ b/hotspot/src/share/vm/opto/loopnode.cpp Tue Feb 17 21:46:39 2015 +0000 @@ -436,6 +436,19 @@ return false; // cyclic loop or this loop trips only once } + if (phi_incr != NULL) { + // check if there is a possiblity of IV overflowing after the first increment + if (stride_con > 0) { + if (init_t->_hi > max_jint - stride_con) { + return false; + } + } else { + if (init_t->_lo < min_jint - stride_con) { + return false; + } + } + } + // ================================================= // ---- SUCCESS! Found A Trip-Counted Loop! ----- // diff -r 74100114a95a -r 9ce801dd67c6 hotspot/test/compiler/loopopts/CountedLoopProblem.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hotspot/test/compiler/loopopts/CountedLoopProblem.java Tue Feb 17 21:46:39 2015 +0000 @@ -0,0 +1,54 @@ +/* + * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * 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. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + * + */ + +/** + * @test + * @bug 8072753 + * @summary Inner loop induction variable increment occurs before compare which causes integer overflow + * @run main/othervm CountedLoopProblem + * + */ + +import java.util.*; + +public class CountedLoopProblem { + public static void main(String[] args) throws Exception { + Random r = new Random(42); + int x = 0; + StringBuilder sb = new StringBuilder(); + for(int i = 0; i < 1000000; ++i) { + int v = Math.abs(r.nextInt()); + sb.append('+').append(v).append('\n'); + x += v; + // To trigger the problem we must OSR in the following loop + // To make the problem 100% reproducible run with -XX:-TieredCompilation -XX:OSROnlyBCI=62 + while(x < 0) x += 1000000000; + sb.append('=').append(x).append('\n'); + } + if (sb.toString().hashCode() != 0xaba94591) { + throw new Exception("Unexpected result"); + } + } +} +