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8265938: C2's conditional move optimization does not handle top Phi
Reviewed-by: chagedorn, kvn, iignatyev
1 parent 5634f20 commit ab2aec2

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3 files changed

+81
-4
lines changed

3 files changed

+81
-4
lines changed

src/hotspot/share/opto/loopopts.cpp

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -718,7 +718,9 @@ Node *PhaseIdealLoop::conditional_move( Node *region ) {
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break;
719719
}
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}
721-
if (phi == NULL) break;
721+
if (phi == NULL || _igvn.type(phi) == Type::TOP) {
722+
break;
723+
}
722724
if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); }
723725
// Move speculative ops
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wq.push(phi);
Lines changed: 72 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,72 @@
1+
/*
2+
* Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
3+
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/**
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* @test
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* @bug 8265938
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* @summary Test conditional move optimization with a TOP PhiNode.
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* @library /test/lib
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* @run main/othervm -XX:CompileCommand=compileonly,compiler.loopopts.TestCMoveWithDeadPhi::test
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* compiler.loopopts.TestCMoveWithDeadPhi
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*/
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package compiler.loopopts;
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35+
import jdk.test.lib.Utils;
36+
37+
public class TestCMoveWithDeadPhi {
38+
39+
static void test(boolean b) {
40+
if (b) {
41+
long l = 42;
42+
for (int i = 0; i < 100; i++) {
43+
if (i < 10) {
44+
l++;
45+
if (i == 5) {
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break;
47+
}
48+
}
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}
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51+
// Infinite loop
52+
for (int j = 0; j < 100; j++) {
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j--;
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}
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}
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}
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public static void main(String[] args) throws Exception {
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// Execute test in own thread because it contains an infinite loop
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Thread thread = new Thread() {
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public void run() {
62+
for (int i = 0; i < 50_000; ++i) {
63+
test((i % 2) == 0);
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}
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}
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};
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// Give thread some time to trigger compilation
68+
thread.setDaemon(true);
69+
thread.start();
70+
Thread.sleep(Utils.adjustTimeout(4000));
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}
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}

test/hotspot/jtreg/compiler/loopopts/TestStrangeControl.java

Lines changed: 6 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
/*
2-
* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
2+
* Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
33
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
44
*
55
* This code is free software; you can redistribute it and/or modify it
@@ -19,20 +19,22 @@
1919
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
2020
* or visit www.oracle.com if you need additional information or have any
2121
* questions.
22-
*
2322
*/
2423

2524
/*
2625
* @test
2726
* @bug 8228888
2827
* @summary Test PhaseIdealLoop::has_local_phi_input() with phi input with non-dominating control.
28+
* @library /test/lib
2929
* @compile StrangeControl.jasm
3030
* @run main/othervm -Xbatch -XX:CompileCommand=inline,compiler.loopopts.StrangeControl::test
3131
* compiler.loopopts.TestStrangeControl
3232
*/
3333

3434
package compiler.loopopts;
3535

36+
import jdk.test.lib.Utils;
37+
3638
public class TestStrangeControl {
3739

3840
public static void main(String[] args) throws Exception {
@@ -42,8 +44,9 @@ public void run() {
4244
StrangeControl.test(42);
4345
}
4446
};
47+
thread.setDaemon(true);
4548
thread.start();
4649
// Give thread executing strange control loop enough time to trigger OSR compilation
47-
Thread.sleep(4000);
50+
Thread.sleep(Utils.adjustTimeout(4000));
4851
}
4952
}

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