From 1fc3b25af40da1afc1ab4d7bab1a0eae267ee43a Mon Sep 17 00:00:00 2001
From: dbuck <unknown>
Date: Thu, 7 Sep 2017 09:21:05 -0400
Subject: [PATCH] 8166742: SIGFPE in C2 Loop IV elimination Reviewed-by: kvn

---
 src/share/vm/opto/loopnode.cpp               |  8 ++-
 test/compiler/loopopts/TestImpossibleIV.java | 51 ++++++++++++++++++++
 2 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 test/compiler/loopopts/TestImpossibleIV.java

diff --git a/src/share/vm/opto/loopnode.cpp b/src/share/vm/opto/loopnode.cpp
index 8f2f22815..f2ecc2755 100644
--- a/src/share/vm/opto/loopnode.cpp
+++ b/src/share/vm/opto/loopnode.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2017, 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
@@ -1773,6 +1773,12 @@ void PhaseIdealLoop::replace_parallel_iv(IdealLoopTree *loop) {
     Node *init2 = phi2->in( LoopNode::EntryControl );
     int stride_con2 = incr2->in(2)->get_int();
 
+    // The ratio of the two strides cannot be represented as an int
+    // if stride_con2 is min_int and stride_con is -1.
+    if (stride_con2 == min_jint && stride_con == -1) {
+      continue;
+    }
+
     // The general case here gets a little tricky.  We want to find the
     // GCD of all possible parallel IV's and make a new IV using this
     // GCD for the loop.  Then all possible IVs are simple multiples of
diff --git a/test/compiler/loopopts/TestImpossibleIV.java b/test/compiler/loopopts/TestImpossibleIV.java
new file mode 100644
index 000000000..e4af508d1
--- /dev/null
+++ b/test/compiler/loopopts/TestImpossibleIV.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2016 Google, 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 8166742
+ * @summary C2 IV elimination throws FPE
+ * @run main/othervm -XX:-TieredCompilation -XX:-BackgroundCompilation TestImpossibleIV
+ * @author Chuck Rasbold rasbold@google.com
+ */
+
+/*
+ * Use -XX:-TieredCompilation to get C2 only.
+ * Use -XX:-BackgroundCompilation to wait for compilation before test exit.
+ */
+
+public class TestImpossibleIV {
+
+  static private void testMethod() {
+    int sum = 0;
+    // A unit count-down loop which has an induction variable with
+    // MIN_VALUE stride.
+    for (int i = 100000; i >= 0; i--) {
+      sum += Integer.MIN_VALUE;
+    }
+  }
+
+  public static void main(String[] args) {
+    testMethod();
+  }
+}
-- 
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