--- old/src/hotspot/share/opto/macro.cpp	2020-01-17 17:14:35.607115849 +0100
+++ new/src/hotspot/share/opto/macro.cpp	2020-01-17 17:14:35.508115854 +0100
@@ -47,9 +47,13 @@
 #include "opto/subnode.hpp"
 #include "opto/type.hpp"
 #include "runtime/sharedRuntime.hpp"
+#include "utilities/macros.hpp"
 #if INCLUDE_G1GC
 #include "gc/g1/g1ThreadLocalData.hpp"
 #endif // INCLUDE_G1GC
+#if INCLUDE_SHENANDOAHGC
+#include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
+#endif
 
 
 //
@@ -458,7 +462,14 @@
       if (val == mem) {
         values.at_put(j, mem);
       } else if (val->is_Store()) {
-        values.at_put(j, val->in(MemNode::ValueIn));
+        Node* n = val->in(MemNode::ValueIn);
+#if INCLUDE_SHENANDOAHGC
+        if (UseShenandoahGC) {
+          BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
+          n = bs->step_over_gc_barrier(n);
+        }
+#endif
+        values.at_put(j, n);
       } else if(val->is_Proj() && val->in(0) == alloc) {
         values.at_put(j, _igvn.zerocon(ft));
       } else if (val->is_Phi()) {
@@ -569,7 +580,14 @@
       // hit a sentinel, return appropriate 0 value
       return _igvn.zerocon(ft);
     } else if (mem->is_Store()) {
-      return mem->in(MemNode::ValueIn);
+      Node* n = mem->in(MemNode::ValueIn);
+#if INCLUDE_SHENANDOAHGC
+      if (UseShenandoahGC) {
+        BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
+        n = bs->step_over_gc_barrier(n);
+      }
+#endif
+      return n;
     } else if (mem->is_Phi()) {
       // attempt to produce a Phi reflecting the values on the input paths of the Phi
       Node_Stack value_phis(a, 8);
@@ -646,6 +664,7 @@
                                    k < kmax && can_eliminate; k++) {
           Node* n = use->fast_out(k);
           if (!n->is_Store() && n->Opcode() != Op_CastP2X &&
+              SHENANDOAHGC_ONLY((!UseShenandoahGC || !ShenandoahBarrierSetC2::is_shenandoah_wb_pre_call(n)) &&)
               !(n->is_ArrayCopy() &&
                 n->as_ArrayCopy()->is_clonebasic() &&
                 n->in(ArrayCopyNode::Dest) == use)) {