8251535: Partial peeling at unsigned test adds incorrect loop exit check
Reviewed-by: chagedorn, neliasso, kvn
This commit is contained in:
parent
5145bed028
commit
7c0d417027
src/hotspot/share/opto
test/hotspot/jtreg/compiler/loopopts
@ -2558,7 +2558,13 @@ IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *lo
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ProjNode* lp_continue = lp_proj->as_Proj();
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ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj();
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if (!lp_exit->is_IfFalse()) {
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// The loop exit condition is (i <u limit) ==> (i >= 0 && i < limit).
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// We therefore can't add a single exit condition.
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return NULL;
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}
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// The loop exit condition is !(i <u limit) ==> (i < 0 || i >= limit).
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// Split out the exit condition (i < 0) for stride < 0 or (i >= limit) for stride > 0.
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Node* limit = NULL;
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if (stride > 0) {
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limit = cmpu->in(2);
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@ -0,0 +1,185 @@
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/*
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* Copyright (c) 2020, 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 8251535
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* @summary Tests partial peeling at unsigned tests.
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* @library /test/lib /
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* @run main/othervm -Xcomp -XX:-TieredCompilation
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* -XX:CompileCommand=compileonly,compiler.loopopts.TestPartialPeelAtUnsignedTests::test*
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* compiler.loopopts.TestPartialPeelAtUnsignedTests
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*/
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package compiler.loopopts;
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import jdk.test.lib.Asserts;
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public class TestPartialPeelAtUnsignedTests {
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/*
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loop:
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i += 1000;
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if (i <u 10_000) {
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goto exit;
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}
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goto loop;
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exit:
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return i;
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C2 splits the unsigned loop exit check to have a
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signed exit test as cut point for partial peeling:
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loop:
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i += 1000;
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if (i < 10_000) { <-- This exit condition is wrong!
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goto exit;
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}
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if (i <u 10_000) {
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goto exit;
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}
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goto loop;
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exit:
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return i;
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*/
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static int test1(int i) {
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boolean cond = false;
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while (!cond) {
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i += 1000;
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// Converted to (i <u 10_000)
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cond = (0 <= i) && (i < 10_000);
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}
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return i;
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}
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/*
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Same as test1 but with a negative stride.
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loop:
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i -= 1000;
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if (i <u 10_000) {
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goto exit;
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}
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goto loop;
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exit:
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return i;
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Converted to:
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loop:
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i -= 1000;
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if (i >= 0) { <-- This exit condition is wrong!
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goto exit;
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}
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if (i <u 10_000) {
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goto exit;
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}
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goto loop;
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exit:
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return i;
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*/
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static int test2(int i) {
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boolean cond = false;
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while (!cond) {
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i -= 1000;
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cond = (0 <= i) && (i < 10_000);
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}
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return i;
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}
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/*
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Same as test1 but with inverted exit condition.
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loop:
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i += 1000;
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if (i <u 10_000) {
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goto loop;
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}
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goto exit;
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exit:
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return i;
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Converted to:
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loop:
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i += 1000;
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if (!(i < 10_000)) { <-- Correct exit condition.
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goto exit;
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}
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if (i <u 10_000) {
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goto loop;
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}
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goto exit;
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exit:
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return i;
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*/
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static int test3(int i) {
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boolean cond = true;
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while (cond) {
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i += 1000;
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cond = (0 <= i) && (i < 10_000);
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}
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return i;
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}
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/*
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Same as test2 but with inverted exit condition.
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loop:
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i -= 1000;
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if (i <u 10_000) {
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goto loop;
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}
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goto exit;
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exit:
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return i;
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Converted to:
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loop:
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i -= 1000;
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if (!(i >= 0)) { <-- Correct exit condition.
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goto exit;
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}
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if (i <u 10_000) {
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goto loop;
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}
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goto exit;
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exit:
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return i;
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*/
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static int test4(int i) {
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boolean cond = true;
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while (cond) {
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i -= 1000;
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cond = (0 <= i) && (i < 10_000);
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}
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return i;
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}
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public static void main(String[] args) {
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Asserts.assertEQ(test1(10_000), 704);
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Asserts.assertEQ(test2(-10_000), 9296);
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Asserts.assertEQ(test3(0), 10000);
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Asserts.assertEQ(test4(9999), -1);
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}
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}
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