8336830: C2: assert(get_loop(lca)->_nest < n_loop->_nest || lca->in(0)->is_NeverBranch()) failed: must not be moved into inner loop

Co-authored-by: Emanuel Peter <epeter@openjdk.org>
Reviewed-by: thartmann, chagedorn, epeter

Author: rwestrel

src/hotspot/share/opto/loopopts.cpp

@@ -1069,7 +1069,7 @@ void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
 #endif
             lca = place_outside_loop(lca, n_loop);
             assert(!n_loop->is_member(get_loop(lca)), "control must not be back in the loop");
-            assert(get_loop(lca)->_nest < n_loop->_nest || lca->in(0)->is_NeverBranch(), "must not be moved into inner loop");
+            assert(get_loop(lca)->_nest < n_loop->_nest || get_loop(lca)->_head->as_Loop()->is_in_infinite_subgraph(), "must not be moved into inner loop");
 
             // Move store out of the loop
             _igvn.replace_node(hook, n->in(MemNode::Memory));

test/hotspot/jtreg/compiler/loopopts/TestSunkNodeInInfiniteLoop.java

@@ -0,0 +1,57 @@
+/*
+ * 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 8336830
+ * @summary C2: assert(get_loop(lca)->_nest < n_loop->_nest || lca->in(0)->is_NeverBranch()) failed: must not be moved into inner loop
+ * @library /test/lib
+ * @run main/othervm -XX:CompileCommand=compileonly,TestSunkNodeInInfiniteLoop::* -Xcomp TestSunkNodeInInfiniteLoop
+ *
+ */
+
+import jdk.test.lib.Utils;
+
+public class TestSunkNodeInInfiniteLoop {
+    public static void main(String[] args) throws InterruptedException {
+        byte[] a = new byte[1];
+        Thread thread = new Thread(() -> test(a));
+        thread.setDaemon(true);
+        thread.start();
+        Thread.sleep(Utils.adjustTimeout(4000));
+    }
+
+    static void test(byte[] a) {
+        // L0:
+        while(true) {
+            int i1 = a.length;
+            // L3:
+            while(true) {
+                int i2 = 0;
+                if ((i1--) <= 0) { break; /* ifle L0 */}
+                a[i2++] = -1;
+                // goto L3
+            }
+        }
+    }
+}