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8161147: jvm crashes when -XX:+UseCountedLoopSafepoints is enabled

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Don't convert loop with safepoint on the backedge to Counted loop

Reviewed-by: kvn
This commit is contained in:
Roland Westrelin 2016-07-25 14:31:42 -07:00
parent eded7ae794
commit 3636d8f3d5
2 changed files with 61 additions and 1 deletions
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10
hotspot/src/share/vm/opto/loopnode.cpp
View File

@ -279,8 +279,16 @@ bool PhaseIdealLoop::is_counted_loop( Node *x, IdealLoopTree *loop ) {
return false;
// Allow funny placement of Safepoint
if (back_control->Opcode() == Op_SafePoint)
if (back_control->Opcode() == Op_SafePoint) {
if (UseCountedLoopSafepoints) {
// Leaving the safepoint on the backedge and creating a
// CountedLoop will confuse optimizations. We can't move the
// safepoint around because its jvm state wouldn't match a new
// location. Give up on that loop.
return false;
}
back_control = back_control->in(TypeFunc::Control);
}
// Controlling test for loop
Node *iftrue = back_control;

52
hotspot/test/compiler/loopopts/TestCountedLoopSafepointBackedge.java Normal file
View File

@ -0,0 +1,52 @@
/*
* Copyright (c) 2016, Red Hat, Inc. 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 8161147
* @summary Safepoint on backedge breaks UseCountedLoopSafepoints
* @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:+UseCountedLoopSafepoints TestCountedLoopSafepointBackedge
*
*/
public class TestCountedLoopSafepointBackedge {
static void test(int[] arr, int inc) {
int i = 0;
for (;;) {
for (int j = 0; j < 10; j++);
arr[i] = i;
i++;
if (i >= 100) {
break;
}
for (int j = 0; j < 10; j++);
}
}
static public void main(String[] args) {
int[] arr = new int[100];
for (int i = 0; i < 20000; i++) {
test(arr, 1);
}
}
}