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8316756: C2 EA fails with "missing memory path" when encountering uns…
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…afe_arraycopy stub call

Co-authored-by: Vladimir Kozlov <>
Reviewed-by: kvn, thartmann, chagedorn
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tobiasholenstein and Vladimir Kozlov committed Jan 17, 2024
1 parent bf666bc commit b891721
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Showing 2 changed files with 86 additions and 1 deletion.
9 changes: 8 additions & 1 deletion src/hotspot/share/opto/escape.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -4006,6 +4006,13 @@ void ConnectionGraph::split_unique_types(GrowableArray<Node *> &alloc_worklist,
if (n == nullptr) {
} else if (n->is_CallLeaf()) {
// Runtime calls with narrow memory input (no MergeMem node)
// get the memory projection
n = n->as_Call()->proj_out_or_null(TypeFunc::Memory);
if (n == nullptr) {
} else if (n->Opcode() == Op_StrCompressedCopy ||
n->Opcode() == Op_EncodeISOArray) {
// get the memory projection
Expand Down Expand Up @@ -4048,7 +4055,7 @@ void ConnectionGraph::split_unique_types(GrowableArray<Node *> &alloc_worklist,
} else if (use->is_MemBar()) {
} else if (use->is_MemBar() || use->is_CallLeaf()) {
if (use->in(TypeFunc::Memory) == n) { // Ignore precedent edge
Expand Down
78 changes: 78 additions & 0 deletions test/hotspot/jtreg/compiler/unsafe/
Original file line number Diff line number Diff line change
@@ -0,0 +1,78 @@
* Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
* 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 if you need additional information or have any
* questions.

* @test
* @bug 8316756
* @summary Test UNSAFE.copyMemory in combination with Escape Analysis
* @library /test/lib
* @modules java.base/jdk.internal.misc
* @run main/othervm -XX:-TieredCompilation -Xbatch -XX:CompileCommand=quiet -XX:CompileCommand=compileonly,compiler.unsafe.UnsafeArrayCopy::test*
* compiler.unsafe.UnsafeArrayCopy

package compiler.unsafe;

import java.lang.reflect.*;
import java.util.*;

import jdk.internal.misc.Unsafe;

public class UnsafeArrayCopy {

private static Unsafe UNSAFE = Unsafe.getUnsafe();

static long SRC_BASE = UNSAFE.allocateMemory(4);
static long DST_BASE = UNSAFE.allocateMemory(4);

static class MyClass {
int x;

static int test() {
MyClass obj = new MyClass(); // Non-escaping to trigger Escape Analysis
UNSAFE.copyMemory(null, SRC_BASE, null, DST_BASE, 4);
obj.x = 42;
return obj.x;

static int[] test2() {
int[] src = new int[4];
int[] dst = new int[4];
MyClass obj = new MyClass();
UNSAFE.copyMemory(src, 0, dst, 0, 4);
obj.x = 42;
dst[1] = obj.x;
return dst;

public static void main(String[] args) {
for (int i = 0; i < 50_000; ++i) {

3 comments on commit b891721

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/backport jdk21u-dev

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@openjdk openjdk bot commented on b891721 Jun 12, 2024

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@TheRealMDoerr the backport was successfully created on the branch backport-TheRealMDoerr-b8917214-master in my personal fork of openjdk/jdk21u-dev. To create a pull request with this backport targeting openjdk/jdk21u-dev:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit b8917214 from the openjdk/jdk repository.

The commit being backported was authored by Tobias Holenstein on 17 Jan 2024 and was reviewed by Vladimir Kozlov, Tobias Hartmann and Christian Hagedorn.


If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk21u-dev:

$ git fetch backport-TheRealMDoerr-b8917214-master:backport-TheRealMDoerr-b8917214-master
$ git checkout backport-TheRealMDoerr-b8917214-master
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push backport-TheRealMDoerr-b8917214-master

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