diff --git a/src/hotspot/share/opto/subnode.cpp b/src/hotspot/share/opto/subnode.cpp index 430bb5b447b..b53110a9b45 100644 --- a/src/hotspot/share/opto/subnode.cpp +++ b/src/hotspot/share/opto/subnode.cpp @@ -733,11 +733,10 @@ const Type* CmpUNode::Value(PhaseGVN* phase) const { int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here const TypeInt* tr1 = TypeInt::make(lo_tr1, hi_tr1, w); const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w); - const Type* cmp1 = sub(tr1, t2); - const Type* cmp2 = sub(tr2, t2); - if (cmp1 == cmp2) { - return cmp1; // Hit! - } + 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); } } } diff --git a/test/hotspot/jtreg/compiler/rangechecks/TestRangeCheckCmpUUnderflow.java b/test/hotspot/jtreg/compiler/rangechecks/TestRangeCheckCmpUUnderflow.java new file mode 100644 index 00000000000..2242b80c005 --- /dev/null +++ b/test/hotspot/jtreg/compiler/rangechecks/TestRangeCheckCmpUUnderflow.java @@ -0,0 +1,57 @@ +/* + * Copyright (c) 2022, 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 8286638 + * @summary Dominator failure because ConvL2I node becomes TOP, kills data-flow, but range-check does not collapse + * due to insufficient overflow/underflow handling in CmpUNode::Value. + * + * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+StressIGVN -Xcomp -XX:-TieredCompilation + * -XX:CompileCommand=compileonly,compiler.rangechecks.TestRangeCheckCmpUUnderflow::* + * -XX:RepeatCompilation=300 + * compiler.rangechecks.TestRangeCheckCmpUUnderflow +*/ + +package compiler.rangechecks; + +public class TestRangeCheckCmpUUnderflow { + volatile int a; + int b[]; + float c[]; + void e() { + int g, f, i; + for (g = 2;; g++) { + for (i = g; i < 1; i++) { + f = a; + c[i - 1] -= b[i]; + } + } + } + public static void main(String[] args) { + try { + TestRangeCheckCmpUUnderflow j = new TestRangeCheckCmpUUnderflow(); + j.e(); + } catch (Exception ex) {} + } +}