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TobiHartmannTobiHartmann
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8273409: Receiver type narrowed by CCP does not always trigger post-parse call devirtualization
Reviewed-by: vlivanov, neliasso
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‎src/hotspot/share/opto/phaseX.cpp‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1967,7 +1967,9 @@ Node *PhaseCCP::transform_once( Node *n ) {
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// TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
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switch( n->Opcode() ) {
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case Op_FastLock: // Revisit FastLocks for lock coarsening
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case Op_CallStaticJava: // Give post-parse call devirtualization a chance
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case Op_CallDynamicJava:
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case Op_FastLock: // Revisit FastLocks for lock coarsening
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case Op_If:
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case Op_CountedLoopEnd:
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case Op_Region:

‎test/hotspot/jtreg/compiler/c2/irTests/TestPostParseCallDevirtualization.java‎

Lines changed: 200 additions & 0 deletions
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@@ -0,0 +1,200 @@
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/*
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* Copyright (c) 2021, 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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package compiler.c2.irTests;
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import java.lang.invoke.MethodHandle;
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import java.lang.invoke.MethodHandles;
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import java.lang.invoke.MethodType;
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import jdk.test.lib.Asserts;
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import compiler.lib.ir_framework.*;
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/*
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* @test
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* @bug 8273409
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* @summary Test that post-parse call devirtualization works as intended.
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* @library /test/lib /
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* @run driver compiler.c2.irTests.TestPostParseCallDevirtualization
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*/
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public class TestPostParseCallDevirtualization {
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public static void main(String[] args) {
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TestFramework framework = new TestFramework();
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Scenario noOSR = new Scenario(0, "-XX:-UseOnStackReplacement");
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Scenario alwaysIncremental = new Scenario(1, "-XX:-UseOnStackReplacement", "-XX:+IgnoreUnrecognizedVMOptions", "-XX:+AlwaysIncrementalInline");
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framework.addScenarios(noOSR, alwaysIncremental).start();
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}
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static interface I {
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public int method();
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}
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static final class A implements I {
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@Override
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public int method() { return 0; };
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}
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static final class B implements I {
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@Override
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public int method() { return 42; };
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}
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static final class C implements I {
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@Override
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public int method() { return -1; };
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}
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static final A a = new A();
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static final B b = new B();
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static final C c = new C();
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static int callHelper(I recv) {
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// Receiver profile is polluted
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return recv.method();
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}
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@Test
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@IR(failOn = {IRNode.DYNAMIC_CALL_OF_METHOD, "method"},
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counts = {IRNode.STATIC_CALL_OF_METHOD, "method", "= 1"})
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public int testDynamicCallWithLoop(B val) {
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// Make sure val is non-null below
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if (val == null) {
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return 0;
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}
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// Loop that triggers loop opts
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I recv = a;
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for (int i = 0; i < 3; ++i) {
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if (i > 1) {
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recv = val;
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}
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}
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// We only know after loop opts that the receiver type is non-null B.
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// Post-parse call devirtualization should then convert the
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// virtual call in the helper method to a static call.
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return callHelper(recv);
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}
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@Run(test = "testDynamicCallWithLoop")
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public void checkTestDynamicCallWithLoop() {
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// Pollute receiver profile with three different
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// types to prevent (bimorphic) inlining.
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callHelper(a);
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callHelper(b);
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callHelper(c);
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Asserts.assertEquals(testDynamicCallWithLoop(b), 42);
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}
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@Test
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@IR(failOn = {IRNode.DYNAMIC_CALL_OF_METHOD, "method"},
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counts = {IRNode.STATIC_CALL_OF_METHOD, "method", "= 1"})
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public int testDynamicCallWithCCP(B val) {
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// Make sure val is non-null below
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if (val == null) {
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return 0;
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}
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// Loop that triggers CCP
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I recv = a;
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for (int i = 0; i < 100; i++) {
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if ((i % 2) == 0) {
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recv = val;
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}
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}
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// We only know after CCP that the receiver type is non-null B.
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// Post-parse call devirtualization should then convert the
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// virtual call in the helper method to a static call.
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return callHelper(recv);
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}
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@Run(test = "testDynamicCallWithCCP")
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public void checkTestDynamicCallWithCCP() {
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// Pollute receiver profile with three different
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// types to prevent (bimorphic) inlining.
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callHelper(a);
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callHelper(b);
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callHelper(c);
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Asserts.assertEquals(testDynamicCallWithCCP(b), 42);
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}
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static final MethodHandle mh1;
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static final MethodHandle mh2;
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static {
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try {
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MethodHandles.Lookup lookup = MethodHandles.lookup();
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mh1 = lookup.findStatic(TestPostParseCallDevirtualization.class, "method1", MethodType.methodType(int.class));
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mh2 = lookup.findStatic(TestPostParseCallDevirtualization.class, "method2", MethodType.methodType(int.class));
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} catch (NoSuchMethodException | IllegalAccessException e) {
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e.printStackTrace();
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throw new RuntimeException("Method handle lookup failed");
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}
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}
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static int method1() { return 0; }
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static int method2() { return 42; }
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@Test
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@IR(failOn = {IRNode.STATIC_CALL_OF_METHOD, "invokeBasic"},
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counts = {IRNode.STATIC_CALL_OF_METHOD, "invokeStatic", "= 1"})
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public int testMethodHandleCallWithLoop() throws Throwable {
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MethodHandle mh = mh1;
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for (int i = 0; i < 3; ++i) {
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if (i > 1) {
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mh = mh2;
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}
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}
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// We only know after loop opts that the receiver is mh2.
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// Post-parse call devirtualization should then convert the
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// virtual call to a static call.
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return (int)mh.invokeExact();
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}
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@Run(test = "testMethodHandleCallWithLoop")
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public void checkTestMethodHandleCallWithLoop() throws Throwable {
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Asserts.assertEquals(testMethodHandleCallWithLoop(), 42);
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}
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@Test
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@IR(failOn = {IRNode.STATIC_CALL_OF_METHOD, "invokeBasic"},
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counts = {IRNode.STATIC_CALL_OF_METHOD, "invokeStatic", "= 1"})
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public int testMethodHandleCallWithCCP() throws Throwable {
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MethodHandle mh = mh1;
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int limit = 0;
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for (int i = 0; i < 100; i++) {
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if ((i % 2) == 0) {
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limit = 1;
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}
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}
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for (int i = 0; i < limit; ++i) {
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mh = mh2;
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}
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// We only know after CCP that the receiver is mh2.
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// Post-parse call devirtualization should then convert the
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// virtual call to a static call.
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return (int)mh.invokeExact();
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}
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@Run(test = "testMethodHandleCallWithCCP")
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public void checkTestMethodHandleCallWithCCP() throws Throwable {
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Asserts.assertEquals(testMethodHandleCallWithCCP(), 42);
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}
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}

‎test/hotspot/jtreg/compiler/lib/ir_framework/IRNode.java‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -115,6 +115,8 @@ public class IRNode {
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public static final String COUNTEDLOOP_MAIN = START + "CountedLoop\\b" + MID + "main" + END;
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public static final String CALL = START + "CallStaticJava" + MID + END;
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public static final String DYNAMIC_CALL_OF_METHOD = COMPOSITE_PREFIX + START + "CallDynamicJava" + MID + IS_REPLACED + END;
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public static final String STATIC_CALL_OF_METHOD = COMPOSITE_PREFIX + START + "CallStaticJava" + MID + IS_REPLACED + END;
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public static final String TRAP = START + "CallStaticJava" + MID + "uncommon_trap.*reason" + END;
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public static final String PREDICATE_TRAP = START + "CallStaticJava" + MID + "uncommon_trap.*predicate" + END;
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public static final String UNSTABLE_IF_TRAP = START + "CallStaticJava" + MID + "uncommon_trap.*unstable_if" + END;

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