diff --git a/src/hotspot/share/opto/phaseX.cpp b/src/hotspot/share/opto/phaseX.cpp index 6a5d836488a..0ec4fef7502 100644 --- a/src/hotspot/share/opto/phaseX.cpp +++ b/src/hotspot/share/opto/phaseX.cpp @@ -1889,13 +1889,23 @@ Node *PhaseCCP::transform_once( Node *n ) { } else if( n->is_Region() ) { // Unreachable region // Note: nn == C->top() n->set_req(0, NULL); // Cut selfreference - // Eagerly remove dead phis to avoid phis copies creation. - for (DUIterator i = n->outs(); n->has_out(i); i++) { - Node* m = n->out(i); - if( m->is_Phi() ) { - assert(type(m) == Type::TOP, "Unreachable region should not have live phis."); - replace_node(m, nn); - --i; // deleted this phi; rescan starting with next position + bool progress = true; + uint max = n->outcnt(); + DUIterator i; + while (progress) { + progress = false; + // Eagerly remove dead phis to avoid phis copies creation. + for (i = n->outs(); n->has_out(i); i++) { + Node* m = n->out(i); + if (m->is_Phi()) { + assert(type(m) == Type::TOP, "Unreachable region should not have live phis."); + replace_node(m, nn); + if (max != n->outcnt()) { + progress = true; + i = n->refresh_out_pos(i); + max = n->outcnt(); + } + } } } } diff --git a/test/hotspot/jtreg/compiler/c2/TestUnreachableRegionDuringCCP.java b/test/hotspot/jtreg/compiler/c2/TestUnreachableRegionDuringCCP.java new file mode 100644 index 00000000000..86209f27a9b --- /dev/null +++ b/test/hotspot/jtreg/compiler/c2/TestUnreachableRegionDuringCCP.java @@ -0,0 +1,63 @@ +/* + * Copyright (c) 2018, 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 8210387 + * @summary Test removal of unreachable regions during CCP. + * @library /test/lib + * @run main/othervm -Xcomp -XX:-TieredCompilation + * -XX:CompileOnly=compiler.c2.TestUnreachableRegionDuringCCP::test + * compiler.c2.TestUnreachableRegionDuringCCP + */ + +package compiler.c2; + +import jdk.test.lib.Asserts; + +public class TestUnreachableRegionDuringCCP { + static int iFld1 = -1; + static int iFld2 = -1; + static int iArrFld[] = new int[100]; + + public static void test() { + int i = 1; + do { + iArrFld[i] = iFld1; + iFld1 = 42; + for (int j = 1; j < 5; j++) { + if (i != 0) { + return; // Always returns + } + iFld2 += j; + } + } while (++i < 10); + } + + public static void main(String[] args) { + test(); + Asserts.assertEQ(iFld1, 42); + Asserts.assertEQ(iFld2, -1); + Asserts.assertEQ(iArrFld[1], -1); + } +}