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8274060: C2: Incorrect computation after JDK-8273454

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Reviewed-by: thartmann, neliasso, chagedorn
This commit is contained in:
Aleksey Shipilev 2021-09-22 08:40:04 +00:00
parent d9872ba3d6
commit c77ebe8874
2 changed files with 84 additions and 3 deletions
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11
src/hotspot/share/opto/mulnode.cpp
View File

@ -63,10 +63,16 @@ Node *MulNode::Ideal(PhaseGVN *phase, bool can_reshape) {
const Type *t2 = phase->type( in(2) );
Node *progress = NULL; // Progress flag
// convert "(-a)*(-b)" into "a*b"
// This code is used by And nodes too, but some conversions are
// only valid for the actual Mul nodes.
uint op = Opcode();
bool real_mul = (op == Op_MulI) || (op == Op_MulL) ||
(op == Op_MulF) || (op == Op_MulD);
// Convert "(-a)*(-b)" into "a*b".
Node *in1 = in(1);
Node *in2 = in(2);
if (in1->is_Sub() && in2->is_Sub()) {
if (real_mul && in1->is_Sub() && in2->is_Sub()) {
if (phase->type(in1->in(1))->is_zero_type() &&
phase->type(in2->in(1))->is_zero_type()) {
set_req(1, in1->in(2));
@ -119,7 +125,6 @@ Node *MulNode::Ideal(PhaseGVN *phase, bool can_reshape) {
// If the right input is a constant, and the left input is a product of a
// constant, flatten the expression tree.
uint op = Opcode();
if( t2->singleton() && // Right input is a constant?
op != Op_MulF && // Float & double cannot reassociate
op != Op_MulD ) {

76
test/hotspot/jtreg/compiler/integerArithmetic/TestNegAnd.java Normal file
View File

@ -0,0 +1,76 @@
/*
* Copyright (c) 2021, 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
* @key randomness
* @bug 8274060
* @summary Test broken transformation (-a) & (-b) = a & b does not happen
*
* @library /test/lib
*
* @run main/othervm -XX:-TieredCompilation -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:CompileCommand="dontinline,TestNegAnd::test*" TestNegAnd
*
*/
import java.util.Random;
import jdk.test.lib.Utils;
import jdk.test.lib.Asserts;
public class TestNegAnd {
private static final Random random = Utils.getRandomInstance();
// Enough cycles to ensure test methods are JIT-ed
private static final int TEST_COUNT = 20_000;
private static int testInt(int a, int b) {
return (-a) & (-b);
}
private static long testLong(long a, long b) {
return (-a) & (-b);
}
private static void runIntTests() {
for (int index = 0; index < TEST_COUNT; index ++) {
int a = random.nextInt();
int b = random.nextInt();
int expected = (-a) & (-b);
int res = testInt(a, b);
Asserts.assertEQ(res, expected);
}
}
private static void runLongTests() {
for (int index = 0; index < TEST_COUNT; index ++) {
long a = random.nextLong();
long b = random.nextLong();
long expected = (-a) & (-b);
long res = testLong(a, b);
Asserts.assertEQ(res, expected);
}
}
public static void main(String[] args) {
runIntTests();
runLongTests();
}
}