689 }
690 
691 bool ArrayCopyNode::may_modify_helper(const TypeOopPtr* t_oop, Node* n, PhaseValues* phase, ArrayCopyNode*& ac) {
692   if (n != nullptr &&
693       n->is_ArrayCopy() &&
694       n->as_ArrayCopy()->may_modify(t_oop, phase)) {
695     ac = n->as_ArrayCopy();
696     return true;
697   }
698   return false;
699 }
700 
701 bool ArrayCopyNode::may_modify(const TypeOopPtr* t_oop, MemBarNode* mb, PhaseValues* phase, ArrayCopyNode*& ac) {
702   if (mb->trailing_expanded_array_copy()) {
703     return true;
704   }
705 
706   Node* c = mb->in(0);
707 
708   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
709   // step over g1 gc barrier if we're at e.g. a clone with ReduceInitialCardMarks off
710   c = bs->step_over_gc_barrier(c);
711 
712   CallNode* call = nullptr;
713   guarantee(c != nullptr, "step_over_gc_barrier failed, there must be something to step to.");
714   if (c->is_Region()) {
715     for (uint i = 1; i < c->req(); i++) {
716       if (c->in(i) != nullptr) {
717         Node* n = c->in(i)->in(0);
718         if (may_modify_helper(t_oop, n, phase, ac)) {
719           assert(c == mb->in(0), "only for clone");
720           return true;
721         }
722       }
723     }
724   } else if (may_modify_helper(t_oop, c->in(0), phase, ac)) {
725 #ifdef ASSERT
726     bool use_ReduceInitialCardMarks = BarrierSet::barrier_set()->is_a(BarrierSet::CardTableBarrierSet) &&
727       static_cast<CardTableBarrierSetC2*>(bs)->use_ReduceInitialCardMarks();
728     assert(c == mb->in(0) || (ac->is_clonebasic() && !use_ReduceInitialCardMarks), "only for clone");
729 #endif
730     return true;

689 }
690 
691 bool ArrayCopyNode::may_modify_helper(const TypeOopPtr* t_oop, Node* n, PhaseValues* phase, ArrayCopyNode*& ac) {
692   if (n != nullptr &&
693       n->is_ArrayCopy() &&
694       n->as_ArrayCopy()->may_modify(t_oop, phase)) {
695     ac = n->as_ArrayCopy();
696     return true;
697   }
698   return false;
699 }
700 
701 bool ArrayCopyNode::may_modify(const TypeOopPtr* t_oop, MemBarNode* mb, PhaseValues* phase, ArrayCopyNode*& ac) {
702   if (mb->trailing_expanded_array_copy()) {
703     return true;
704   }
705 
706   Node* c = mb->in(0);
707 
708   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();


709 
710   CallNode* call = nullptr;
711   guarantee(c != nullptr, "step_over_gc_barrier failed, there must be something to step to.");
712   if (c->is_Region()) {
713     for (uint i = 1; i < c->req(); i++) {
714       if (c->in(i) != nullptr) {
715         Node* n = c->in(i)->in(0);
716         if (may_modify_helper(t_oop, n, phase, ac)) {
717           assert(c == mb->in(0), "only for clone");
718           return true;
719         }
720       }
721     }
722   } else if (may_modify_helper(t_oop, c->in(0), phase, ac)) {
723 #ifdef ASSERT
724     bool use_ReduceInitialCardMarks = BarrierSet::barrier_set()->is_a(BarrierSet::CardTableBarrierSet) &&
725       static_cast<CardTableBarrierSetC2*>(bs)->use_ReduceInitialCardMarks();
726     assert(c == mb->in(0) || (ac->is_clonebasic() && !use_ReduceInitialCardMarks), "only for clone");
727 #endif
728     return true;