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8323972: C2 compilation fails with assert(!x->as_Loop()->is_loop_nest_inner_loop()) failed: loop was transformed

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Reviewed-by: chagedorn, epeter
This commit is contained in:
Roland Westrelin 2024-03-19 07:56:53 +00:00
parent c0fc9563a7
commit e1b0af29e4
2 changed files with 51 additions and 1 deletions
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10
src/hotspot/share/opto/loopnode.cpp
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@ -940,12 +940,20 @@ bool PhaseIdealLoop::create_loop_nest(IdealLoopTree* loop, Node_List &old_new) {
// inner_iters_max may not fit in a signed integer (iterating from
// Long.MIN_VALUE to Long.MAX_VALUE for instance). Use an unsigned
// min.
Node* inner_iters_actual = MaxNode::unsigned_min(inner_iters_max, inner_iters_limit, TypeInteger::make(0, iters_limit, Type::WidenMin, bt), _igvn);
const TypeInteger* inner_iters_actual_range = TypeInteger::make(0, iters_limit, Type::WidenMin, bt);
Node* inner_iters_actual = MaxNode::unsigned_min(inner_iters_max, inner_iters_limit, inner_iters_actual_range, _igvn);
Node* inner_iters_actual_int;
if (bt == T_LONG) {
inner_iters_actual_int = new ConvL2INode(inner_iters_actual);
_igvn.register_new_node_with_optimizer(inner_iters_actual_int);
// When the inner loop is transformed to a counted loop, a loop limit check is not expected to be needed because
// the loop limit is less or equal to max_jint - stride - 1 (if stride is positive but a similar argument exists for
// a negative stride). We add a CastII here to guarantee that, when the counted loop is created in a subsequent loop
// opts pass, an accurate range of values for the limits is found.
const TypeInt* inner_iters_actual_int_range = TypeInt::make(0, iters_limit, Type::WidenMin);
inner_iters_actual_int = new CastIINode(outer_head, inner_iters_actual_int, inner_iters_actual_int_range, ConstraintCastNode::UnconditionalDependency);
_igvn.register_new_node_with_optimizer(inner_iters_actual_int);
} else {
inner_iters_actual_int = inner_iters_actual;
}

42
test/hotspot/jtreg/compiler/longcountedloops/TestInaccurateInnerLoopLimit.java Normal file
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@ -0,0 +1,42 @@
/*
* Copyright (c) 2024, 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 8323972
* @summary C2 compilation fails with assert(!x->as_Loop()->is_loop_nest_inner_loop()) failed: loop was transformed
*
* @run main/othervm -Xcomp -XX:CompileCommand=compileonly,TestInaccurateInnerLoopLimit::test* -XX:-TieredCompilation TestInaccurateInnerLoopLimit
*
*/
public class TestInaccurateInnerLoopLimit {
public static void main(String args[]) {
test();
}
public static void test() {
for (long i = 9223372034707292164L; i > 9223372034707292158L; i += -2L) { }
}
}