8258272: LoadVectorMaskedNode can't be replaced by zero con

Reviewed-by: chagedorn, vlivanov
This commit is contained in:
Nils Eliasson 2021-01-13 09:16:08 +00:00
parent a99df45b7c
commit 5567530916
2 changed files with 63 additions and 2 deletions
src/hotspot/share/opto
test/hotspot/jtreg/compiler/arraycopy

@ -2044,10 +2044,12 @@ const Type* LoadNode::Value(PhaseGVN* phase) const {
}
}
if (is_instance) {
bool is_vect = (_type->isa_vect() != NULL);
if (is_instance && !is_vect) {
// If we have an instance type and our memory input is the
// programs's initial memory state, there is no matching store,
// so just return a zero of the appropriate type
// so just return a zero of the appropriate type -
// except if it is vectorized - then we have no zero constant.
Node *mem = in(MemNode::Memory);
if (mem->is_Parm() && mem->in(0)->is_Start()) {
assert(mem->as_Parm()->_con == TypeFunc::Memory, "must be memory Parm");

@ -0,0 +1,59 @@
/*
* Copyright (c) 2021, 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 8258272
* @summary Test that LoadVectorMaskedNodes works when the source array is known to only contain zeros
*
* @run main/othervm -XX:-BackgroundCompilation -XX:CompileCommand=dontinline,*::testArrayCopy*
* compiler.arraycopy.TestArrayCopyMaskedWithZeroSrc
*/
package compiler.arraycopy;
import java.util.*;
public class TestArrayCopyMaskedWithZeroSrc {
public static void main(String[] args) {
TestArrayCopyMaskedWithZeroSrc t = new TestArrayCopyMaskedWithZeroSrc();
t.test();
}
void test() {
for (int i = 0; i < 20000; i++) {
testArrayCopy1(3);
}
}
// src is allocated locally - it is known it only contains zeros.
// The copy of will exapnd into LoadVectorMasked on AVX512 machines
// LoadNode::value will try to replace the load from src with a zero constant.
byte [] testArrayCopy1(int partial_len) {
byte [] src = new byte[5];
byte [] dest = Arrays.copyOf(src, partial_len);
return dest;
}
}