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8299959: C2: CmpU::Value must filter overflow computation against local sub computation

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Reviewed-by: kvn, chagedorn, roland
This commit is contained in:
Emanuel Peter 2023-01-19 07:37:50 +00:00
parent 5b0af1a80b
commit 5f66024e95
2 changed files with 72 additions and 3 deletions
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11
src/hotspot/share/opto/subnode.cpp
View File

@ -779,6 +779,9 @@ const Type* CmpUNode::Value(PhaseGVN* phase) const {
if (t2 == TypeInt::INT) { // Compare to bottom?
return bottom_type();
}
const Type* t_sub = sub(t1, t2); // compare based on immediate inputs
uint in1_op = in1->Opcode();
if (in1_op == Op_AddI || in1_op == Op_SubI) {
// The problem rise when result of AddI(SubI) may overflow
@ -831,13 +834,15 @@ const Type* CmpUNode::Value(PhaseGVN* phase) const {
const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w);
const TypeInt* cmp1 = sub(tr1, t2)->is_int();
const TypeInt* cmp2 = sub(tr2, t2)->is_int();
// compute union, so that cmp handles all possible results from the two cases
return cmp1->meet(cmp2);
// Compute union, so that cmp handles all possible results from the two cases
const Type* t_cmp = cmp1->meet(cmp2);
// Pick narrowest type, based on overflow computation and on immediate inputs
return t_sub->filter(t_cmp);
}
}
}
return sub(t1, t2); // Local flavor of type subtraction
return t_sub;
}
bool CmpUNode::is_index_range_check() const {

64
test/hotspot/jtreg/compiler/rangechecks/TestRangeCheckCmpUOverflowVsSub.java Normal file
View File

@ -0,0 +1,64 @@
/*
* 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 8299959
* @summary In CmpU::Value, the sub computation may be narrower than the overflow computation.
*
* @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+StressCCP -Xcomp -XX:-TieredCompilation
* -XX:CompileCommand=compileonly,compiler.rangechecks.TestRangeCheckCmpUOverflowVsSub::test
* -XX:RepeatCompilation=50
* compiler.rangechecks.TestRangeCheckCmpUOverflowVsSub
*/
package compiler.rangechecks;
public class TestRangeCheckCmpUOverflowVsSub {
static int arr[] = new int[400];
public static void main(String[] strArr) {
for (int i = 0; i < 10; i++) {
test(); // repeat for multiple compilations
}
}
static void test() {
for(int i = 0; i < 50_000; i++) {} //empty loop - trigger OSR faster
int val;
int zero = arr[5];
int i = 1;
do {
for (int j = 1; j < 3; j++) {
for (int k = 2; k > i; k -= 3) {
try {
val = arr[i + 1] % k;
val = arr[i - 1] % zero;
val = arr[k - 1];
} catch (ArithmeticException e) {} // catch div by zero
}
}
} while (++i < 3);
}
}