6700047: C2 failed in idom_no_update

Summary: partial peeling shouldn't place clones into loop
Reviewed-by: kvn

src/share/vm/opto/loopopts.cpp

@@ -1891,18 +1891,19 @@ void PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, N
     _igvn.hash_delete(use);
     use->set_req(j, n_clone);
     _igvn._worklist.push(use);
+    Node* use_c;
     if (!use->is_Phi()) {
-      Node* use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
-      set_ctrl(n_clone, use_c);
-      assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
-      get_loop(use_c)->_body.push(n_clone);
+      use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
     } else {
       // Use in a phi is considered a use in the associated predecessor block
-      Node *prevbb = use->in(0)->in(j);
-      set_ctrl(n_clone, prevbb);
-      assert(!loop->is_member(get_loop(prevbb)), "should be outside loop");
-      get_loop(prevbb)->_body.push(n_clone);
+      use_c = use->in(0)->in(j);
     }
+    if (use_c->is_CountedLoop()) {
+      use_c = use_c->in(LoopNode::EntryControl);
+    }
+    set_ctrl(n_clone, use_c);
+    assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
+    get_loop(use_c)->_body.push(n_clone);
     _igvn.register_new_node_with_optimizer(n_clone);
 #if !defined(PRODUCT)
     if (TracePartialPeeling) {

test/compiler/6700047/Test6700047.java

+/*
+ * Copyright 2008 Sun Microsystems, 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/**
+ * @test
+ * @bug 6700047
+ * @summary C2 failed in idom_no_update
+ * @run main Test6700047
+ */
+
+public class Test6700047 {
+    public static void main(String[] args) {
+        for (int i = 0; i < 100000; i++) {
+            intToLeftPaddedAsciiBytes();
+        }
+    }
+
+    public static int intToLeftPaddedAsciiBytes() {
+        int offset = 40;
+        int q;
+        int r;
+        int         i   = 100;
+        int result = 1;
+        while (offset > 0) {
+            q = (i * 52429);
+            r = i;
+            offset--;
+            i = q;
+            if (i == 0) {
+                break;
+            }
+        }
+        if (offset > 0) {
+            for(int j = 0; j < offset; j++) {
+                result++;
+            }
+        }
+        return result;
+    }
+}