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8330163: C2: improve CMoveNode::Value() when condition is always true or false

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Reviewed-by: chagedorn, kvn
This commit is contained in:
Roland Westrelin 2024-04-17 10:48:35 +00:00
parent d2f9a1eb97
commit 9445047d05
2 changed files with 78 additions and 0 deletions
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7
src/hotspot/share/opto/movenode.cpp
View File

@ -169,6 +169,13 @@ const Type* CMoveNode::Value(PhaseGVN* phase) const {
if (phase->type(in(IfTrue)) == Type::TOP || phase->type(in(IfFalse)) == Type::TOP) {
return Type::TOP;
}
if (phase->type(in(Condition)) == TypeInt::ZERO) {
return phase->type(in(IfFalse))->filter(_type); // Always pick left (false) input
}
if (phase->type(in(Condition)) == TypeInt::ONE) {
return phase->type(in(IfTrue))->filter(_type); // Always pick right (true) input
}
const Type* t = phase->type(in(IfFalse))->meet_speculative(phase->type(in(IfTrue)));
return t->filter(_type);
}

71
test/hotspot/jtreg/compiler/c2/irTests/TestCMoveCCP.java Normal file
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@ -0,0 +1,71 @@
/*
* Copyright (c) 2024, Red Hat 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.
*/
package compiler.c2.irTests;
import compiler.lib.ir_framework.*;
/*
* @test
* @bug 8330163
* @summary C2: improve CMoveNode::Value() when condition is always true or false
* @library /test/lib /
* @run driver compiler.c2.irTests.TestCMoveCCP
*/
public class TestCMoveCCP {
private static volatile int volatileField;
public static void main(String[] args) {
TestFramework.run();
}
@Test
@IR(failOn = { IRNode.COUNTED_LOOP, IRNode.LOOP })
private static void test1() {
int i = -1;
testHelper1(i);
}
@ForceInline
private static void testHelper1(int i) {
do {
if (i != 1) {
if (i < 0) { // Converted to CMoveI
i = 50;
}
volatileField = 42;
}
i *= 2;
// i = 100 on first iteration when called from test1
} while (i != 100);
}
@Run(test = "test1")
@Warmup(10000)
private static void testRunner1() {
test1();
testHelper1(1);
}
}