89 lines
3.2 KiB
Java
89 lines
3.2 KiB
Java
/*
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* Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
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* 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 8296389
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* @summary Peeling of Irreducible loop can lead to NeverBranch being visited from either side
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* @run main/othervm -Xcomp -XX:-TieredCompilation -XX:PerMethodTrapLimit=0
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* -XX:CompileCommand=compileonly,TestPhaseCFGNeverBranchToGotoMain::test
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* TestPhaseCFGNeverBranchToGotoMain
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*/
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/*
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* @test
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* @bug 8296389
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* @compile TestPhaseCFGNeverBranchToGoto.jasm
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* @summary Peeling of Irreducible loop can lead to NeverBranch being visited from either side
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* @run main/othervm -Xcomp -XX:-TieredCompilation -XX:PerMethodTrapLimit=0
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* -XX:CompileCommand=compileonly,TestPhaseCFGNeverBranchToGoto::test
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* TestPhaseCFGNeverBranchToGoto
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*/
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public class TestPhaseCFGNeverBranchToGotoMain {
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public static void main (String[] args) {
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test(false, false);
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}
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public static void test(boolean flag1, boolean flag2) {
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if (flag1) { // runtime check, avoid infinite loop
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int a = 77;
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int b = 0;
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do { // empty loop
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a--;
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b++;
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} while (a > 0);
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// a == 0, b == 77 - after first loop-opts phase
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int p = 0;
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for (int i = 0; i < 4; i++) {
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if ((i % 2) == 0) {
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p = 1;
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}
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}
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// p == 1 - after second loop-opts phase (via unrolling)
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// in first loop-opts phase we have 2x unrolling, 4x after second
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int x = 1;
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if (flag2) {
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x = 3;
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} // have region here, so that NeverBranch does not get removed
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do { // infinite loop
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do {
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// NeverBranch inserted here, during loop-opts 1
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x *= 2;
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if (p == 0) { // reason for peeling in loop-opts 1
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// after we know that p == 1, we lose this exit
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break;
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}
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// once we know that b == 77, we lose exit
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} while (b == 77);
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// after we lost both exits above, this loop gets cut off
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int y = 5;
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do {
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y *= 3;
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} while (b == 77);
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} while (true);
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}
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}
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}
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