8269088: C2 fails with assert(!n->is_Store() && !n->is_LoadStore()) failed: no node with a side effect

Reviewed-by: kvn, iveresov, neliasso

src/hotspot/share/opto/loopopts.cpp

@@ -949,6 +949,9 @@ void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
               assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state");
             }
 #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)->Opcode() == Op_NeverBranch, "must not be moved into inner loop");
 
             // Move store out of the loop
             _igvn.replace_node(hook, n->in(MemNode::Memory));
@@ -1147,7 +1150,9 @@ Node* PhaseIdealLoop::place_outside_loop(Node* useblock, IdealLoopTree* loop) co
   // Pick control right outside the loop
   for (;;) {
     Node* dom = idom(useblock);
-    if (loop->is_member(get_loop(dom))) {
+    if (loop->is_member(get_loop(dom)) ||
+        // NeverBranch nodes are not assigned to the loop when constructed
+        (dom->Opcode() == Op_NeverBranch && loop->is_member(get_loop(dom->in(0))))) {
       break;
     }
     useblock = dom;

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

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2021, 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 8269088
+ * @summary C2 fails with assert(!n->is_Store() && !n->is_LoadStore()) failed: no node with a side effect
+ *
+ * @requires vm.gc.Serial
+ * @run main/othervm -Xcomp -XX:CompileOnly=TestStoreSunkInInnerLoop -XX:CompileCommand=quiet -XX:+UseSerialGC -Xmx256m TestStoreSunkInInnerLoop
+ *
+ */
+
+public class TestStoreSunkInInnerLoop {
+
+    public static final int N = 400;
+
+    public static int iFld=-10622;
+    public static long lArrFld[]=new long[N];
+    public float fArrFld[][]=new float[N][N];
+
+    public void mainTest() {
+
+        int i8=-10584, i10=37284, i11=38, i13=-238, i14=-18473, i15=-53564;
+        boolean b1=false;
+
+        TestStoreSunkInInnerLoop.iFld -= TestStoreSunkInInnerLoop.iFld;
+        for (i8 = 224; i8 > 7; i8 -= 2) {
+            i10 = 1;
+            while (++i10 < 232) {
+                TestStoreSunkInInnerLoop.iFld += i8;
+            }
+            for (i11 = 8; i11 < 232; ++i11) {
+                if (b1) continue;
+                TestStoreSunkInInnerLoop.lArrFld[i11] += i10;
+            }
+        }
+        i13 = 1;
+        do {
+            switch ((i13 % 2) + 126) {
+            case 126:
+                for (i14 = 102; i14 > 2; i14 -= 3) {
+                    fArrFld[i13][(-126 >>> 1) % N] -= i15;
+                }
+                break;
+            case 127:
+                i15 = (i13 % i10);
+                break;
+            default:
+            }
+        } while (++i13 < 247);
+    }
+
+    public static void main(String[] strArr) {
+        TestStoreSunkInInnerLoop _instance = new TestStoreSunkInInnerLoop();
+        for (int i = 0; i < 10; i++ ) {
+            _instance.mainTest();
+        }
+    }
+}