--- old/src/hotspot/share/opto/mathexactnode.cpp	2018-01-12 14:21:02.095926522 +0100
+++ new/src/hotspot/share/opto/mathexactnode.cpp	2018-01-12 14:21:01.655907188 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2018, 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
@@ -117,10 +117,25 @@
   return SubHelper<OverflowSubLNode>::will_overflow(v1, v2);
 }
 
+// this method is here to avoid undefined behaviour when doing -val and val is min_jlong
+// -min_jlong overflows and goes back to being min_jlong
+static jlong negate_jlong(jlong val) {
+  if (val == min_jlong) {
+    return min_jlong;
+  }
+  return -val;
+}
+
 bool OverflowMulLNode::will_overflow(jlong val1, jlong val2) const {
-    jlong result = val1 * val2;
-    jlong ax = (val1 < 0 ? -val1 : val1);
-    jlong ay = (val2 < 0 ? -val2 : val2);
+    julong v1 = (julong) val1;
+    julong v2 = (julong) val2;
+    // the multiplication here is done as unsigned to avoid undefined behaviour which 
+    // can be used by the compiler to assume that the check further down (result / val2 != val1)
+    // is always false and break the overflow check
+    julong tmp = v1 * v2;
+    jlong result = (jlong) tmp;
+    jlong ax = (val1 < 0 ? negate_jlong(val1) : val1);
+    jlong ay = (val2 < 0 ? negate_jlong(val2) : val2);
 
     bool overflow = false;
     if ((ax | ay) & CONST64(0xFFFFFFFF00000000)) {