--- old/src/cpu/ppc/vm/vm_version_ppc.cpp	2015-03-11 17:09:29.244253262 +0000
+++ new/src/cpu/ppc/vm/vm_version_ppc.cpp	2015-03-11 17:09:29.134256652 +0000
@@ -172,6 +172,11 @@
     FLAG_SET_DEFAULT(UseSHA512Intrinsics, false);
   }
 
+  // This machine does not allow unaligned memory accesses
+  if (! FLAG_IS_DEFAULT(UseUnalignedAccesses)) {
+    warning("Unaligned memory access is not available on this CPU");
+    FLAG_SET_DEFAULT(UseUnalignedAccesses, false);
+  }
 }
 
 void VM_Version::print_features() {