--- old/src/cpu/x86/vm/c1_Runtime1_x86.cpp	2017-03-12 11:11:14.718867850 +0100
+++ new/src/cpu/x86/vm/c1_Runtime1_x86.cpp	2017-03-12 11:11:14.662868094 +0100
@@ -1675,6 +1675,10 @@
 
     case g1_post_barrier_slow_id:
       {
+        // avoid touching CardTableModRefBS if not G1
+        // FIXME: This looks like an upstream bug.
+        if (!UseG1GC) break;
+
         StubFrame f(sasm, "g1_post_barrier", dont_gc_arguments);