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/*
* Copyright (c) 2025, 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 8335747
* @summary Integer overflow in LoopLimit::Value during PhaseIdealLoop::split_thru_phi
* @run main/othervm -Xbatch -XX:CompileCommand=compileonly,TestLoopLimitOverflowDuringSplitThruPhi::test
* compiler.loopopts.TestLoopLimitOverflowDuringSplitThruPhi
* @run driver compiler.loopopts.TestLoopLimitOverflowDuringSplitThruPhi
*/
package compiler.loopopts;
public class TestLoopLimitOverflowDuringSplitThruPhi {
public static void main(String[] args) {
int[] a = new int[1005];
for (int i = 0; i < 20_000; i++) {
test(i % 2 == 0, a);
}
}
static void test(boolean flag, int[] a) {
int x = flag ? 1000 : 2147483647;
// Creates a Phi(1000, 2147483647)
// We do loop-predication, and add a
// LoopLimitNode(init=0, limit=x, stride=4)
//
// Later, we find try to PhaseIdealLoop::split_thru_phi
// the LoopLimitNode, through the Phi(1000, 2147483647).
//
// This creates a temporary
// LoopLimitNode(init=0, limit=2147483647, stride=4)
//
// And then we get this:
// init_con 0
// limit_con 2147483647
// stride_con 4
// trip_count 536870912
// final_int -2147483648
// final_con 2147483648
//
for (int i = 0; i < x; i+=4 /* works for at least 2..64 */) {
// Break before going out of bounds
// but with quadratic check to not affect limit.
if (i * i > 1000_000) { return; }
a[i] = 34;
}
}
}
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