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8305324: C2: Wrong execution of vectorizing Interger.reverseBytes

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Reviewed-by: kvn, pli
This commit is contained in:
quadhier 2023-04-12 17:08:26 +00:00 committed by Vladimir Kozlov
parent 87017b5199
commit 19380d74e4
2 changed files with 63 additions and 6 deletions
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13
src/hotspot/share/opto/superword.cpp
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@ -3934,14 +3934,15 @@ void SuperWord::compute_vector_element_type() {
}
if (same_type) {
// In any Java arithmetic operation, operands of small integer types
// (boolean, byte, char & short) should be promoted to int first. As
// vector elements of small types don't have upper bits of int, for
// RShiftI or AbsI operations, the compiler has to know the precise
// signedness info of the 1st operand. These operations shouldn't be
// vectorized if the signedness info is imprecise.
// (boolean, byte, char & short) should be promoted to int first.
// During narrowed integer type backward propagation, for some operations
// like RShiftI, Abs, and ReverseBytesI,
// the compiler has to know the higher order bits of the 1st operand,
// which will be lost in the narrowed type. These operations shouldn't
// be vectorized if the higher order bits info is imprecise.
const Type* vt = vtn;
int op = in->Opcode();
if (VectorNode::is_shift_opcode(op) || op == Op_AbsI) {
if (VectorNode::is_shift_opcode(op) || op == Op_AbsI || op == Op_ReverseBytesI) {
Node* load = in->in(1);
if (load->is_Load() && in_bb(load) && (velt_type(load)->basic_type() == T_INT)) {
// Only Load nodes distinguish signed (LoadS/LoadB) and unsigned

56
test/hotspot/jtreg/compiler/vectorization/TestNarrowedIntegerReverseBytes.java Normal file
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@ -0,0 +1,56 @@
/*
* Copyright (c) 2023, 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 8305324
* @summary C2: Wrong execution of vectorizing Interger.reverseBytes
* @run main/othervm -Xcomp -XX:-TieredCompilation -XX:CompileCommand=compileonly,compiler.vectorization.TestNarrowedIntegerReverseBytes::* compiler.vectorization.TestNarrowedIntegerReverseBytes
*/
package compiler.vectorization;
public class TestNarrowedIntegerReverseBytes {
static final int LEN = 33;
static byte byteArray[] = new byte[LEN];
static void test() {
for (int i = 0; i < LEN; i++) {
byteArray[i] = (byte) Integer.reverseBytes(i);
}
}
public static void main(String[] strArr) {
for (int i = 0; i < 2; i++) {
test();
}
for (int i = 0; i < byteArray.length; i++) {
if (byteArray[i] != 0) {
System.err.println("FAILED: all the elements should be zero");
System.exit(1);
}
}
System.out.println("PASSED");
}
}