--- a/src/hotspot/share/opto/memnode.cpp	Thu Nov 01 11:42:59 2018 -0400
+++ b/src/hotspot/share/opto/memnode.cpp	Wed Nov 07 20:21:35 2018 +0100
@@ -1697,7 +1697,7 @@
     // as to alignment, which will therefore produce the smallest
     // possible base offset.
     const int min_base_off = arrayOopDesc::base_offset_in_bytes(T_BYTE);
-    const bool off_beyond_header = ((uint)off >= (uint)min_base_off);
+    const bool off_beyond_header = (off >= min_base_off);
 
     // Try to constant-fold a stable array element.
     if (FoldStableValues && !is_mismatched_access() && ary->is_stable()) {
@@ -1734,7 +1734,7 @@
         && Opcode() != Op_LoadKlass && Opcode() != Op_LoadNKlass) {
       // t might actually be lower than _type, if _type is a unique
       // concrete subclass of abstract class t.
-      if (off_beyond_header) {  // is the offset beyond the header?
+      if (off_beyond_header || off == Type::OffsetBot) {  // is the offset beyond the header?
         const Type* jt = t->join_speculative(_type);
         // In any case, do not allow the join, per se, to empty out the type.
         if (jt->empty() && !t->empty()) {