8317121: vector_masked_load instruction is moved too early after JDK-8286941
Co-authored-by: Vladimir Ivanov <vlivanov@openjdk.org> Co-authored-by: Tobias Hartmann <thartmann@openjdk.org> Co-authored-by: Dean Long <dlong@openjdk.org> Reviewed-by: thartmann, vlivanov, epeter
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@ -593,8 +593,13 @@ Node* LoadNode::find_previous_arraycopy(PhaseValues* phase, Node* ld_alloc, Node
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Node* dest = ac->in(ArrayCopyNode::Dest);
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if (dest == ld_base) {
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const TypeX *ld_offs_t = phase->type(ld_offs)->isa_intptr_t();
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if (ac->modifies(ld_offs_t->_lo, ld_offs_t->_hi, phase, can_see_stored_value)) {
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const TypeX* ld_offs_t = phase->type(ld_offs)->isa_intptr_t();
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assert(!ld_offs_t->empty(), "dead reference should be checked already");
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// Take into account vector or unsafe access size
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jlong ld_size_in_bytes = (jlong)memory_size();
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jlong offset_hi = ld_offs_t->_hi + ld_size_in_bytes - 1;
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offset_hi = MIN2(offset_hi, (jlong)(TypeX::MAX->_hi)); // Take care for overflow in 32-bit VM
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if (ac->modifies(ld_offs_t->_lo, (intptr_t)offset_hi, phase, can_see_stored_value)) {
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return ac;
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}
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if (!can_see_stored_value) {
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118
test/hotspot/jtreg/compiler/vectorization/TestMaskedVectors.java
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118
test/hotspot/jtreg/compiler/vectorization/TestMaskedVectors.java
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@ -0,0 +1,118 @@
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/*
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* Copyright (c) 2023, 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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/*
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* @test
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* @bug 8317121
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* @summary Test masked vectors and unsafe access to memory modified by arraycopy
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* @requires vm.compiler2.enabled
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* @modules java.base/jdk.internal.misc
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* @library /test/lib /
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* @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions -XX:-TieredCompilation -Xbatch -XX:CompileCommand=quiet -XX:CompileCommand=compileonly,TestMaskedVectors::test* -XX:+StressLCM -XX:+StressGCM -XX:StressSeed=2210259638 TestMaskedVectors
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* @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions -XX:-TieredCompilation -Xbatch -XX:CompileCommand=quiet -XX:CompileCommand=compileonly,TestMaskedVectors::test* -XX:+StressLCM -XX:+StressGCM TestMaskedVectors
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*/
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import java.lang.reflect.*;
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import java.util.*;
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import jdk.internal.misc.Unsafe;
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public class TestMaskedVectors {
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private static Unsafe UNSAFE = Unsafe.getUnsafe();
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private static final long BASE_OFFSET = UNSAFE.arrayBaseOffset(byte[].class);
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static void testLoadVectorMasked(byte[] src, byte[] dst, int len) {
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byte[] tmp = new byte[64];
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// (3) The LoadVectorMasked is found to be dependent on below arraycopy and
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// therefore scheduled just below it. As a result, the LoadVectorMasked misses the
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// updated elements at index 16..48 and dst will contain incorrect values.
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System.arraycopy(src, 0, tmp, 0, 16);
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// (2) The LoadVectorMasked is incorrectly found to be independent of this arraycopy
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// because the LoadVectorMasked has offset 0 whereas the arraycopy writes offset >= 16.
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// The problem is that MemNode::find_previous_store() -> LoadNode::find_previous_arraycopy()
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// -> ArrayCopyNode::modifies does not account for the size of the load.
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System.arraycopy(src, 0, tmp, 16, 48);
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// (1) The following arraycopy is expanded into a LoadVectorMasked and a
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// StoreVectorMasked in PhaseMacroExpand::generate_partial_inlining_block().
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System.arraycopy(tmp, 0, dst, 0, len);
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}
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static long testUnsafeGetLong(byte[] src) {
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byte[] tmp = new byte[16];
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// (3) The unsafe load is found to be dependent on below arraycopy and
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// therefore scheduled just below it. As a result, the unsafe load misses the
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// updated elements at index 1..16 and therefore returns an incorrect result.
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System.arraycopy(src, 0, tmp, 0, 16);
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// (2) The unsafe load is incorrectly found to be independent of this arraycopy
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// because the load has offset 0 in 'tmp' whereas the arraycopy writes offsets >= 1.
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// The problem is that MemNode::find_previous_store() -> LoadNode::find_previous_arraycopy()
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// -> ArrayCopyNode::modifies does not account for the size of the load.
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System.arraycopy(src, 0, tmp, 1, 15);
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// (1) Below unsafe load reads the first 8 (byte) array elements.
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return UNSAFE.getLong(tmp, BASE_OFFSET);
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}
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public static void main(String[] args) {
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// Initialize src array with increasing byte values
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byte[] src = new byte[64];
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for (byte i = 0; i < src.length; ++i) {
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src[i] = (byte)i;
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}
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// Compute expected outputs once
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byte[] golden1 = new byte[64];
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testLoadVectorMasked(src, golden1, 64);
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long golden2 = testUnsafeGetLong(src);
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// Trigger compilation of test methods and verify the results
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for (int i = 0; i < 50_000; ++i) {
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int len = i % 32;
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byte[] dst = new byte[len];
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testLoadVectorMasked(src, dst, len);
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boolean error = false;
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for (int j = 0; j < dst.length; ++j) {
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if (dst[j] != golden1[j]) {
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System.out.println("Incorrect value of element " + j + ": Expected " + golden1[j] + " but got " + dst[j]);
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error = true;
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}
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}
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if (error) {
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throw new RuntimeException("Test LoadVectorMasked failed");
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}
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long res = testUnsafeGetLong(src);
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if (res != golden2) {
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throw new RuntimeException("Incorrect result in test UnsafeGetLong: Expected " + golden2 + " but got " + res);
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}
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}
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}
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}
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