1418     return node->in(LoadBarrierNode::Oop);
1419   }
1420 
1421   // 3. This step checks for the phi corresponding to an optimized load barrier expansion
1422   if (node->is_Phi()) {
1423     PhiNode* phi = node->as_Phi();
1424     Node* n = phi->in(1);
1425     if (n != NULL && (n->is_LoadBarrierSlowReg() ||  n->is_LoadBarrierWeakSlowReg())) {
1426       assert(c == node, "projections from step 1 should only be seen before macro expansion");
1427       return phi->in(2);
1428     }
1429   }
1430 
1431   return c;
1432 }
1433 
1434 bool ZBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const {
1435   return type == T_OBJECT || type == T_ARRAY;
1436 }
1437 























1438 // == Verification ==
1439 
1440 #ifdef ASSERT
1441 
1442 static bool look_for_barrier(Node* n, bool post_parse, VectorSet& visited) {
1443   if (visited.test_set(n->_idx)) {
1444     return true;
1445   }
1446 
1447   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1448     Node* u = n->fast_out(i);
1449     if (u->is_LoadBarrier()) {
1450     } else if ((u->is_Phi() || u->is_CMove()) && !post_parse) {
1451       if (!look_for_barrier(u, post_parse, visited)) {
1452         return false;
1453       }
1454     } else if (u->Opcode() == Op_EncodeP || u->Opcode() == Op_DecodeN) {
1455       if (!look_for_barrier(u, post_parse, visited)) {
1456         return false;
1457       }

1418     return node->in(LoadBarrierNode::Oop);
1419   }
1420 
1421   // 3. This step checks for the phi corresponding to an optimized load barrier expansion
1422   if (node->is_Phi()) {
1423     PhiNode* phi = node->as_Phi();
1424     Node* n = phi->in(1);
1425     if (n != NULL && (n->is_LoadBarrierSlowReg() ||  n->is_LoadBarrierWeakSlowReg())) {
1426       assert(c == node, "projections from step 1 should only be seen before macro expansion");
1427       return phi->in(2);
1428     }
1429   }
1430 
1431   return c;
1432 }
1433 
1434 bool ZBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const {
1435   return type == T_OBJECT || type == T_ARRAY;
1436 }
1437 
1438 bool ZBarrierSetC2::final_graph_reshaping(Compile* compile, Node* n, uint opcode) const {
1439   bool handled;
1440   switch (opcode) {
1441     case Op_LoadBarrierSlowReg:
1442     case Op_LoadBarrierWeakSlowReg:
1443 #ifdef ASSERT
1444       if (VerifyOptoOopOffsets) {
1445         MemNode* mem  = n->as_Mem();
1446         // Check to see if address types have grounded out somehow.
1447         const TypeInstPtr* tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
1448         ciInstanceKlass* k = tp->klass()->as_instance_klass();
1449         bool oop_offset_is_sane = k->contains_field_offset(tp->offset());
1450         assert(!tp || oop_offset_is_sane, "");
1451       }
1452 #endif
1453       handled = true;
1454       break;
1455     default:
1456       handled = false;
1457   }
1458   return handled;
1459 }
1460 
1461 // == Verification ==
1462 
1463 #ifdef ASSERT
1464 
1465 static bool look_for_barrier(Node* n, bool post_parse, VectorSet& visited) {
1466   if (visited.test_set(n->_idx)) {
1467     return true;
1468   }
1469 
1470   for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1471     Node* u = n->fast_out(i);
1472     if (u->is_LoadBarrier()) {
1473     } else if ((u->is_Phi() || u->is_CMove()) && !post_parse) {
1474       if (!look_for_barrier(u, post_parse, visited)) {
1475         return false;
1476       }
1477     } else if (u->Opcode() == Op_EncodeP || u->Opcode() == Op_DecodeN) {
1478       if (!look_for_barrier(u, post_parse, visited)) {
1479         return false;
1480       }