8208275: C2 crash in Node::add_req(Node*)
Split-if optimization should not process (dead) counted loops. Reviewed-by: roland
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@ -267,6 +267,13 @@ static Node* split_if(IfNode *iff, PhaseIterGVN *igvn) {
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Node* predicate_c = NULL;
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Node* predicate_x = NULL;
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bool counted_loop = r->is_CountedLoop();
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if (counted_loop) {
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// Ignore counted loops for now because the split-if logic does not work
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// in all the cases (for example, with strip mined loops). Also, above
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// checks only pass for already degraded loops without a tripcount phi
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// and these are essentially dead and will go away during igvn.
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return NULL;
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}
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Node *region_c = new RegionNode(req_c + 1);
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Node *phi_c = con1;
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@ -0,0 +1,79 @@
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/*
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* Copyright (c) 2018, 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 8208275
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* @summary Test removal of strip mined loop with only one iteration.
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* @run main/othervm -XX:-TieredCompilation -Xcomp
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* -XX:CompileCommand=compileonly,compiler.loopopts.TestOneIterationStripMined::test*
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* compiler.loopopts.TestOneIterationStripMined
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*/
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package compiler.loopopts;
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public class TestOneIterationStripMined {
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static int iField;
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static volatile Object oField;
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public static void test1(int val) {
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iField = 0; // Do something
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// This loop is strip mined and then removed because it has only one iteration.
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for (int i = 0; i < 1; ++i) {
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// Trigger split-if optimization
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if (val == 0) {
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break;
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}
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val = 0;
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}
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}
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// Same as test1 but with a volatile Object field
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// (will trigger a different failure mode)
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public static void test2(int val) {
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oField = null;
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for (int i = 0; i < 1; ++i) {
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if (val == 0) {
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break;
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}
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val = 0;
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}
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}
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// Same as test1 but without any code outside loop body
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// (will trigger a different failure mode)
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public static void test3(int val) {
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for (int i = 0; i < 1; ++i) {
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if (val == 0) {
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break;
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}
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val = 0;
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}
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}
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public static void main(String[] args) {
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test1(0);
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test2(0);
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test3(0);
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}
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}
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