diff --git a/src/hotspot/share/opto/subnode.cpp b/src/hotspot/share/opto/subnode.cpp index b42761bc17c..1d626e9cb9c 100644 --- a/src/hotspot/share/opto/subnode.cpp +++ b/src/hotspot/share/opto/subnode.cpp @@ -1403,6 +1403,34 @@ Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) { return new BoolNode( cmp, _test.commute() ); } + // Change "bool eq/ne (cmp (and X 16) 16)" into "bool ne/eq (cmp (and X 16) 0)". + if (cop == Op_CmpI && + (_test._test == BoolTest::eq || _test._test == BoolTest::ne) && + cmp1->Opcode() == Op_AndI && cmp2->Opcode() == Op_ConI && + cmp1->in(2)->Opcode() == Op_ConI) { + const TypeInt *t12 = phase->type(cmp2)->isa_int(); + const TypeInt *t112 = phase->type(cmp1->in(2))->isa_int(); + if (t12 && t12->is_con() && t112 && t112->is_con() && + t12->get_con() == t112->get_con() && is_power_of_2(t12->get_con())) { + Node *ncmp = phase->transform(new CmpINode(cmp1, phase->intcon(0))); + return new BoolNode(ncmp, _test.negate()); + } + } + + // Same for long type: change "bool eq/ne (cmp (and X 16) 16)" into "bool ne/eq (cmp (and X 16) 0)". + if (cop == Op_CmpL && + (_test._test == BoolTest::eq || _test._test == BoolTest::ne) && + cmp1->Opcode() == Op_AndL && cmp2->Opcode() == Op_ConL && + cmp1->in(2)->Opcode() == Op_ConL) { + const TypeLong *t12 = phase->type(cmp2)->isa_long(); + const TypeLong *t112 = phase->type(cmp1->in(2))->isa_long(); + if (t12 && t12->is_con() && t112 && t112->is_con() && + t12->get_con() == t112->get_con() && is_power_of_2(t12->get_con())) { + Node *ncmp = phase->transform(new CmpLNode(cmp1, phase->longcon(0))); + return new BoolNode(ncmp, _test.negate()); + } + } + // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)". // The XOR-1 is an idiom used to flip the sense of a bool. We flip the // test instead. diff --git a/test/hotspot/jtreg/compiler/c2/TestBit.java b/test/hotspot/jtreg/compiler/c2/TestBit.java new file mode 100644 index 00000000000..2e3d5248363 --- /dev/null +++ b/test/hotspot/jtreg/compiler/c2/TestBit.java @@ -0,0 +1,112 @@ +/* + * Copyright (c) 2020, 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. + */ + +package compiler.c2; + +import jdk.test.lib.process.OutputAnalyzer; +import jdk.test.lib.process.ProcessTools; + +/* + * @test + * @bug 8247408 + * @summary C2 should convert ((var&16) == 16) to ((var&16) != 0) for power-of-two constants + * @library /test/lib / + * + * @run main/othervm compiler.c2.TestBit + * + * @requires os.arch=="aarch64" | os.arch=="amd64" | os.arch == "ppc64le" + * @requires vm.debug == true & vm.flavor == "server" & !vm.graal.enabled + */ +public class TestBit { + + static void runTest(String testName) throws Exception { + String className = "compiler.c2.TestBit"; + String[] procArgs = { + "-XX:+PrintOptoAssembly", + "-XX:CompileCommand=compileonly," + className + "::tst*", + className, testName}; + + ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(procArgs); + OutputAnalyzer output = new OutputAnalyzer(pb.start()); + + String expectedTestBitInstruction = + "ppc64le".equals(System.getProperty("os.arch")) ? "ANDI" : + "aarch64".equals(System.getProperty("os.arch")) ? "tb" : + "amd64".equals(System.getProperty("os.arch")) ? "test" : null; + + if (expectedTestBitInstruction != null) { + output.shouldContain(expectedTestBitInstruction); + } else { + System.err.println("unexpected os.arch"); + } + } + + static final int ITER = 100000; // ~ Tier4CompileThreshold + compilation time + + // dummy volatile variable + public static volatile long c = 0; + + // C2 is expected to generate test bit instruction on the test + static void tstBitLong(long value) { + if (1L == (1L & value)) { + c++; + } else { + c--; + } + } + + // C2 is expected to generate test bit instruction on the test + static void tstBitInt(int value) { + if (1 == (1 & value)) { + c++; + } else { + c--; + } + } + + public static void main(String[] args) throws Exception { + if (args.length == 0) { + // Fork VMs to check their debug compiler output + runTest("tstBitLong"); + runTest("tstBitInt"); + } + if (args.length > 0) { + // We are in a forked VM to execute the named test + String testName = args[0]; + switch (testName) { + case "tstBitLong": + for (int i = 0; i < ITER; i++) { + tstBitLong(i % 2); + } + break; + case "tstBitInt": + for (int i = 0; i < ITER; i++) { + tstBitInt(i % 2); + } + break; + default: + throw new RuntimeException("unexpected test name " + testName); + } + } + } +} diff --git a/test/micro/org/openjdk/bench/vm/compiler/BitTest.java b/test/micro/org/openjdk/bench/vm/compiler/BitTest.java new file mode 100644 index 00000000000..35669cd0ffa --- /dev/null +++ b/test/micro/org/openjdk/bench/vm/compiler/BitTest.java @@ -0,0 +1,52 @@ +/* + * Copyright (c) 2020, 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. + */ +package org.openjdk.bench.vm.compiler; + +import org.openjdk.jmh.annotations.Benchmark; +import org.openjdk.jmh.annotations.BenchmarkMode; +import org.openjdk.jmh.annotations.Mode; +import org.openjdk.jmh.annotations.OutputTimeUnit; + + +import java.util.concurrent.TimeUnit; + +@BenchmarkMode(Mode.AverageTime) +@OutputTimeUnit(TimeUnit.NANOSECONDS) +public class BitTest { + + private static final int COUNT = 1000; + + @Benchmark + public int bitTestAndBranch() { + int dummy = 0; + for (int value = 0; value < COUNT; value++) { + dummy++; + if ((value & 32) == 32) { + dummy = value ^ dummy; + } else { + dummy = value ^ value; + } + } + return dummy; + } +}