--- a/src/hotspot/share/runtime/arguments.cpp	Thu Jun 28 07:00:35 2018 +0200
+++ b/src/hotspot/share/runtime/arguments.cpp	Thu Jun 28 07:22:59 2018 +0200
@@ -3900,13 +3900,13 @@
   jint result = set_ergonomics_flags();
   if (result != JNI_OK) return result;
 
-  set_shared_spaces_flags();
-
   // Set heap size based on available physical memory
   set_heap_size();
 
   GCConfig::arguments()->initialize();
 
+  set_shared_spaces_flags();
+
   // Initialize Metaspace flags and alignments
   Metaspace::ergo_initialize();
 

--- a/test/hotspot/jtreg/runtime/appcds/sharedStrings/IncompatibleOptions.java	Thu Jun 28 07:00:35 2018 +0200
+++ b/test/hotspot/jtreg/runtime/appcds/sharedStrings/IncompatibleOptions.java	Thu Jun 28 07:22:59 2018 +0200
@@ -39,6 +39,7 @@
  */
 
 import jdk.test.lib.Asserts;
+import jdk.test.lib.Platform;
 import jdk.test.lib.process.OutputAnalyzer;
 
 import sun.hotspot.code.Compiler;
@@ -62,6 +63,9 @@
 
         // Uncompressed OOPs
         testDump(1, "-XX:+UseG1GC", "-XX:-UseCompressedOops", COOPS_DUMP_WARNING, true);
+        if (Platform.isLinux() && Platform.isX64()) {
+            testDump(1, "-XX:+UnlockExperimentalVMOptions", "-XX:+UseZGC", COOPS_DUMP_WARNING, true);
+        }
 
         // incompatible GCs
         testDump(2, "-XX:+UseParallelGC", "", GC_WARNING, false);