src/hotspot/share/opto/macro.cpp

*** 708,717 ****
--- 708,719 ----
            NOT_PRODUCT(fail_eliminate = "NULL or TOP memory";)
            can_eliminate = false;
          } else {
            safepoints.append_if_missing(sfpt);
          }
+       } else if (use->is_ValueType() && use->isa_ValueType()->get_oop() == res) {
+         // ok to eliminate
        } else if (use->Opcode() != Op_CastP2X) { // CastP2X is used by card mark
          if (use->is_Phi()) {
            if (use->outcnt() == 1 && use->unique_out()->Opcode() == Op_Return) {
              NOT_PRODUCT(fail_eliminate = "Object is return value";)
            } else {
*** 1042,1051 ****
--- 1044,1057 ----
          if (src->outcnt() == 0 && !src->is_top()) {
            _igvn.remove_dead_node(src);
          }
  
          _igvn._worklist.push(ac);
+       } else if (use->is_ValueType()) {
+         assert(use->isa_ValueType()->get_oop() == res, "unexpected value type use");
+          _igvn.rehash_node_delayed(use);
+         use->isa_ValueType()->set_oop(_igvn.zerocon(T_VALUETYPE));
        } else {
          eliminate_gc_barrier(use);
        }
        j -= (oc1 - res->outcnt());
      }