8196296: Lucene test crashes C2 compilation
Summary: Prevent merging of back to back ifs if one is a counted loop end.
Reviewed-by: kvn, thartmann
--- a/src/hotspot/share/opto/loopnode.cpp Fri Jan 26 13:13:19 2018 -0800
+++ b/src/hotspot/share/opto/loopnode.cpp Tue Jan 30 09:08:44 2018 +0100
@@ -1260,6 +1260,10 @@
assert(inner_cl->is_strip_mined(), "inner loop should be strip mined");
Node* inner_iv_phi = inner_cl->phi();
if (inner_iv_phi == NULL) {
+ IfNode* outer_le = outer_loop_end();
+ Node* iff = igvn->transform(new IfNode(outer_le->in(0), outer_le->in(1), outer_le->_prob, outer_le->_fcnt));
+ igvn->replace_node(outer_le, iff);
+ inner_cl->clear_strip_mined();
return;
}
CountedLoopEndNode* inner_cle = inner_cl->loopexit();
--- a/src/hotspot/share/opto/loopopts.cpp Fri Jan 26 13:13:19 2018 -0800
+++ b/src/hotspot/share/opto/loopopts.cpp Tue Jan 30 09:08:44 2018 +0100
@@ -1036,7 +1036,7 @@
bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) {
- if (!n->is_If()) {
+ if (!n->is_If() || n->is_CountedLoopEnd()) {
return false;
}
if (!n->in(0)->is_Region()) {
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/compiler/loopopts/TestStripMinedBackToBackIfs.java Tue Jan 30 09:08:44 2018 +0100
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2018, Red Hat, Inc. 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 8196296
+ * @summary Bad graph when unrolled loop bounds conflicts with range checks
+ *
+ * @run main/othervm -XX:-BackgroundCompilation -XX:+IgnoreUnrecognizedVMOptions -XX:LoopUnrollLimit=0 TestStripMinedBackToBackIfs
+ *
+ */
+
+
+public class TestStripMinedBackToBackIfs {
+ public static void main(String[] args) {
+ for (int i = 0; i < 20_000; i++) {
+ test(100);
+ }
+ }
+
+ private static double test(int limit) {
+ double v = 1;
+ for (int i = 0; i < limit; i++) {
+ v = v * 4;
+ // We don't want this test to be merged with identical
+ // loop end test
+ if (i+1 < limit) {
+ v = v * 2;
+ }
+ }
+ return v;
+ }
+}