107     // no_ctrl, but that doesn't buy much latitude.
108     Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, T_BYTE, adr_type);
109     __ if_then(card_val, BoolTest::ne, dirty);
110   }
111 
112   // Smash dirty value into card
113   __ store(__ ctrl(), card_adr, dirty, T_BYTE, adr_type, MemNode::unordered);
114 
115   if (UseCondCardMark) {
116     __ end_if();
117   }
118 
119   // Final sync IdealKit and GraphKit.
120   kit->final_sync(ideal);
121 }
122 
123 bool CardTableBarrierSetC2::use_ReduceInitialCardMarks() {
124   return ReduceInitialCardMarks;
125 }
126 
127 void CardTableBarrierSetC2::eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const {
128   assert(node->Opcode() == Op_CastP2X, "ConvP2XNode required");
129   Node *shift = node->unique_out();
130   Node *addp = shift->unique_out();
131   for (DUIterator_Last jmin, j = addp->last_outs(jmin); j >= jmin; --j) {
132     Node *mem = addp->last_out(j);
133     if (UseCondCardMark && mem->is_Load()) {
134       assert(mem->Opcode() == Op_LoadB, "unexpected code shape");
135       // The load is checking if the card has been written so
136       // replace it with zero to fold the test.
137       macro->replace_node(mem, macro->intcon(0));
138       continue;






139     }
140     assert(mem->is_Store(), "store required");
141     macro->replace_node(mem, mem->in(MemNode::Memory));
142   }
143 }
144 
145 bool CardTableBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, bool is_clone_instance, ArrayCopyPhase phase) const {
146   bool is_oop = is_reference_type(type);
147   return is_oop && (!tightly_coupled_alloc || !use_ReduceInitialCardMarks());
148 }

107     // no_ctrl, but that doesn't buy much latitude.
108     Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, T_BYTE, adr_type);
109     __ if_then(card_val, BoolTest::ne, dirty);
110   }
111 
112   // Smash dirty value into card
113   __ store(__ ctrl(), card_adr, dirty, T_BYTE, adr_type, MemNode::unordered);
114 
115   if (UseCondCardMark) {
116     __ end_if();
117   }
118 
119   // Final sync IdealKit and GraphKit.
120   kit->final_sync(ideal);
121 }
122 
123 bool CardTableBarrierSetC2::use_ReduceInitialCardMarks() {
124   return ReduceInitialCardMarks;
125 }
126 
127 void CardTableBarrierSetC2::eliminate_gc_barrier(PhaseIterGVN* igvn, Node* node) const {
128   assert(node->Opcode() == Op_CastP2X, "ConvP2XNode required");
129   for (DUIterator_Last imin, i = node->last_outs(imin); i >= imin; --i) {
130     Node* shift = node->last_out(i);
131     for (DUIterator_Last jmin, j = shift->last_outs(jmin); j >= jmin; --j) {
132       Node* addp = shift->last_out(j);
133       for (DUIterator_Last kmin, k = addp->last_outs(kmin); k >= kmin; --k) {
134         Node* mem = addp->last_out(k);
135         if (UseCondCardMark && mem->is_Load()) {
136           assert(mem->Opcode() == Op_LoadB, "unexpected code shape");
137           // The load is checking if the card has been written so
138           // replace it with zero to fold the test.
139           igvn->replace_node(mem, igvn->intcon(0));
140           continue;
141         }
142         assert(mem->is_Store(), "store required");
143         igvn->replace_node(mem, mem->in(MemNode::Memory));
144       }
145     }


146   }
147 }
148 
149 bool CardTableBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, bool is_clone_instance, ArrayCopyPhase phase) const {
150   bool is_oop = type == T_OBJECT || type == T_ARRAY;
151   return is_oop && (!tightly_coupled_alloc || !use_ReduceInitialCardMarks());
152 }