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8301489: C1: ShortLoopOptimizer might lift instructions before their …
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…inputs

Reviewed-by: thartmann, rcastanedalo
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danielogh authored and TobiHartmann committed Jun 27, 2023
1 parent 990e3a7 commit 73d7aa1
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29 changes: 28 additions & 1 deletion src/hotspot/share/c1/c1_ValueMap.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -359,6 +359,33 @@ LoopInvariantCodeMotion::LoopInvariantCodeMotion(ShortLoopOptimizer *slo, Global
}
}

class CheckInsertionPoint : public ValueVisitor {
private:
Value _insert;
bool _valid = true;

void visit(Value* vp) {
assert(*vp != nullptr, "value should not be null");
if (_insert->dominator_depth() < (*vp)->dominator_depth()) {
_valid = false;
}
}

public:
bool is_valid() { return _valid; }
CheckInsertionPoint(Value insert)
: _insert(insert) {
assert(insert != nullptr, "insertion point should not be null");
}
};

// Check that insertion point has higher dom depth than all inputs to cur
static bool is_dominated_by_inputs(Instruction* insertion_point, Instruction* cur) {
CheckInsertionPoint v(insertion_point);
cur->input_values_do(&v);
return v.is_valid();
}

void LoopInvariantCodeMotion::process_block(BlockBegin* block) {
TRACE_VALUE_NUMBERING(tty->print_cr("processing block B%d", block->block_id()));

Expand Down Expand Up @@ -394,7 +421,7 @@ void LoopInvariantCodeMotion::process_block(BlockBegin* block) {
cur_invariant = is_invariant(cvt->value());
}

if (cur_invariant) {
if (cur_invariant && is_dominated_by_inputs(_insertion_point, cur)) {
// perform value numbering and mark instruction as loop-invariant
_gvn->substitute(cur);

Expand Down
116 changes: 116 additions & 0 deletions test/hotspot/jtreg/compiler/c1/Test8301489.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,116 @@
/*
* 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 8301489
* @summary ShortLoopOptimizer might lift instructions before their inputs
* @requires vm.compiler1.enabled
* @run main/othervm -Xcomp -XX:TieredStopAtLevel=1
* -XX:CompileOnly=compiler.c1.Test8301489::*
* compiler.c1.Test8301489
*/


package compiler.c1;

public class Test8301489 {
static int c = 0;
static int[] arr = {};

static void op2Test(int a, int b) {
// Implicit edges created during dom calculation to exception handler
if (a < 0) {
b = 0;
}
// Create two branches into next loop header block
try {
int l = arr.length;
for (int i = 0; i < l; i++) {
int d = arr[i] + arr[i];
}
}
// Exception handler as predecessor of the next loop header block
catch (ArithmeticException e) {}

// op2(a, b) as candidate for hoisting: operands are loop invariant
while (a + b < b) {}
// op2(a, b) should not be hoisted above 'if (a < 0) {...}' block
}

static void arrayLengthTest() {
float [] newArr = new float[c];

try {
for (float f : newArr) {}
}
catch (ArrayIndexOutOfBoundsException e) {}

while (54321 < newArr.length) {
newArr[c] = 123.45f;
}
}

static void negateTest(int a) {
if (a <= 111) {
a = -111;
}

int f = 0;
try {
int l = arr.length;
f--;
}
catch (NegativeArraySizeException e) {}

while (-a < f) {
f--;
}
}

static void convertTest(int a) {
if (c == 0) {
a = 0;
}

long tgt = 10;

try {
String s = String.valueOf(c);
}
catch (NumberFormatException e) {}

while ((long)a != tgt) {
tgt--;
}
}

public static void main(String[] args) {
for (int i = 0; i < 3; i++) {
op2Test(12, 34);
arrayLengthTest();
negateTest(-778);
convertTest(4812);
}
}
}

5 comments on commit 73d7aa1

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@GoeLin
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@GoeLin GoeLin commented on 73d7aa1 Sep 22, 2023

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/backport jdk21u

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@openjdk openjdk bot commented on 73d7aa1 Sep 22, 2023

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@GoeLin the backport was successfully created on the branch GoeLin-backport-73d7aa1d in my personal fork of openjdk/jdk21u. To create a pull request with this backport targeting openjdk/jdk21u: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 73d7aa1d from the openjdk/jdk repository.

The commit being backported was authored by Daniel Skantz on 27 Jun 2023 and was reviewed by Tobias Hartmann and Roberto Castañeda Lozano.

Thanks!

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:

$ git fetch https://github.com/openjdk-bots/jdk21u.git GoeLin-backport-73d7aa1d:GoeLin-backport-73d7aa1d
$ git checkout GoeLin-backport-73d7aa1d
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk21u.git GoeLin-backport-73d7aa1d

@GoeLin
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@GoeLin GoeLin commented on 73d7aa1 Oct 4, 2023

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/backport jdk17u-dev

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@openjdk openjdk bot commented on 73d7aa1 Oct 4, 2023

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@GoeLin the backport was successfully created on the branch GoeLin-backport-73d7aa1d in my personal fork of openjdk/jdk17u-dev. To create a pull request with this backport targeting openjdk/jdk17u-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 73d7aa1d from the openjdk/jdk repository.

The commit being backported was authored by Daniel Skantz on 27 Jun 2023 and was reviewed by Tobias Hartmann and Roberto Castañeda Lozano.

Thanks!

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/jdk17u-dev:

$ git fetch https://github.com/openjdk-bots/jdk17u-dev.git GoeLin-backport-73d7aa1d:GoeLin-backport-73d7aa1d
$ git checkout GoeLin-backport-73d7aa1d
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk17u-dev.git GoeLin-backport-73d7aa1d

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