--- old/src/hotspot/share/gc/shared/gcArguments.cpp	2018-11-19 14:08:36.098591800 -0800
+++ new/src/hotspot/share/gc/shared/gcArguments.cpp	2018-11-19 14:08:35.034190400 -0800
@@ -28,6 +28,7 @@
 #include "runtime/arguments.hpp"
 #include "runtime/globals.hpp"
 #include "runtime/globals_extension.hpp"
+#include "utilities/defaultStream.hpp"
 #include "utilities/macros.hpp"
 
 void GCArguments::initialize() {
@@ -54,3 +55,18 @@
     FLAG_SET_CMDLINE(bool, ClassUnloadingWithConcurrentMark, false);
   }
 }
+
+bool GCArguments::check_args_consistency() {
+  bool status = true;
+  if (!FLAG_IS_DEFAULT(AllocateHeapAt) && !FLAG_IS_DEFAULT(AllocateOldGenAt)) {
+    jio_fprintf(defaultStream::error_stream(),
+      "AllocateHeapAt and AllocateOldGenAt cannot be used together.\n");
+    status = false;
+  }
+  if (!FLAG_IS_DEFAULT(AllocateOldGenAt) && (UseSerialGC || UseConcMarkSweepGC || UseEpsilonGC || UseZGC)) {
+    jio_fprintf(defaultStream::error_stream(),
+      "AllocateOldGenAt not supported for selected GC.\n");
+    status = false;
+  }
+  return status;
+}