8202950: C2: assert(found_sfpt) failed: no node in loop that's not input to safepoint

Reviewed-by: neliasso, kvn

src/hotspot/share/opto/loopopts.cpp

@@ -1667,6 +1667,18 @@ void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new,
         continue;
       }
 
+      // If use is referenced through control edge... (idx == 0)
+      if (mode == IgnoreStripMined && idx == 0) {
+        LoopNode *head = loop->_head->as_Loop();
+        if (head->is_strip_mined() && is_dominator(head->outer_loop_exit(), prev)) {
+          // That node is outside the inner loop, leave it outside the
+          // outer loop as well to not confuse verification code.
+          assert(!loop->_parent->is_member(use_loop), "should be out of the outer loop");
+          _igvn.replace_input_of(use, 0, head->outer_loop_exit());
+          continue;
+        }
+      }
+
       while(!outer_loop->is_member(get_loop(cfg))) {
         prev = cfg;
         cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg);

test/hotspot/jtreg/compiler/loopstripmining/UnexpectedPinnedNodeInOuterLoop.java

@@ -0,0 +1,57 @@
+/*
+ * 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 8202950
+ * @summary C2: assert(found_sfpt) failed: no node in loop that's not input to safepoint
+ *
+ * @run main/othervm -Xcomp -Xbatch -XX:CompileOnly=UnexpectedPinnedNodeInOuterLoop -XX:-TieredCompilation UnexpectedPinnedNodeInOuterLoop
+ *
+ */
+
+public class UnexpectedPinnedNodeInOuterLoop {
+
+    public static final int N = 400;
+
+    public static volatile float fFld=0.488F;
+    public static volatile int iFld=143;
+
+    public static void lMeth(int i2) {
+        int i20=95, i21=-163, i22=-11, iArr[]=new int[N], iArr2[]=new int[N];
+        byte by1=-97;
+
+        for (i20 = 15; 253 > i20; ++i20) {
+            iFld += i21;
+            for (i22 = 1; 7 > i22; i22++) {
+                iArr[i20 + 1] >>= i20;
+            }
+            fFld = i2;
+            iArr2[i20] -= (int)2.302F;
+        }
+    }
+
+    public static void main(String[] strArr) {
+        lMeth(0);
+    }
+}