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8247307: C2: Loop array fill stub routines are not called
Ignore safepoint polling use of CountedLoopNode when matching loop array fill pattern.

Reviewed-by: kvn, thartmann
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Pengfei Li committed Jun 28, 2020
1 parent bdab5a0 commit ac4f14c386a74d1f52d66690cd7e0941cbc1c177
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Showing 3 changed files with 120 additions and 5 deletions.
@@ -1507,6 +1507,12 @@ void VM_Version::get_processor_features() {
// Modern processors allow misaligned memory operations for vectors.
AlignVector = !UseUnalignedLoadStores;
}
if (FLAG_IS_DEFAULT(OptimizeFill)) {
// 8247307: On x86, the auto-vectorized loop array fill code shows
// better performance than the array fill stubs. We should reenable
// this after the x86 stubs get improved.
OptimizeFill = false;
}
#endif // COMPILER2

if (FLAG_IS_DEFAULT(AllocatePrefetchInstr)) {
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 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
@@ -3642,10 +3642,21 @@ bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& st
for (SimpleDUIterator iter(n); iter.has_next(); iter.next()) {
Node* use = iter.get();
if (!lpt->_body.contains(use)) {
msg = "node is used outside loop";
// lpt->_body.dump();
msg_node = n;
break;
if (n->is_CountedLoop() && n->as_CountedLoop()->is_strip_mined()) {
// In strip-mined counted loops, the CountedLoopNode may be
// used by the address polling node of the outer safepoint.
// Skip this use because it's safe.
#ifdef ASSERT
Node* sfpt = n->as_CountedLoop()->outer_safepoint();
Node* polladr = sfpt->in(TypeFunc::Parms+0);
assert(use == polladr, "the use should be a safepoint polling");
#endif
continue;
} else {
msg = "node is used outside loop";
msg_node = n;
break;
}
}
}
}
@@ -0,0 +1,98 @@
/*
* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2020, Arm Limited. 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 org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;

import java.util.concurrent.TimeUnit;
import java.util.Arrays;

@State(Scope.Benchmark)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public class ArrayFill {
@Param("65536") private int size;

private byte[] ba;
private short[] sa;
private int[] ia;

@Setup
public void setup() {
ba = new byte[size];
sa = new short[size];
ia = new int[size];
}

@Benchmark
public void fillByteArray() {
for (int i = 0; i < size; i++) {
ba[i] = (byte) 123;
}
}

@Benchmark
public void fillShortArray() {
for (int i = 0; i < size; i++) {
sa[i] = (short) 12345;
}
}

@Benchmark
public void fillIntArray() {
for (int i = 0; i < size; i++) {
ia[i] = 1234567890;
}
}

@Benchmark
public void zeroByteArray() {
for (int i = 0; i < size; i++) {
ba[i] = 0;
}
}

@Benchmark
public void zeroShortArray() {
for (int i = 0; i < size; i++) {
sa[i] = 0;
}
}

@Benchmark
public void zeroIntArray() {
for (int i = 0; i < size; i++) {
ia[i] = 0;
}
}
}

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