1100 // The Right Thing with def-use info.
1101 //
1102 // You cannot bury the 'this' Node inside of a graph reshape.  If the reshaped
1103 // graph uses the 'this' Node it must be the root.  If you want a Node with
1104 // the same Opcode as the 'this' pointer use 'clone'.
1105 //
1106 Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
1107   return NULL;                  // Default to being Ideal already
1108 }
1109 
1110 // Some nodes have specific Ideal subgraph transformations only if they are
1111 // unique users of specific nodes. Such nodes should be put on IGVN worklist
1112 // for the transformations to happen.
1113 bool Node::has_special_unique_user() const {
1114   assert(outcnt() == 1, "match only for unique out");
1115   Node* n = unique_out();
1116   int op  = Opcode();
1117   if (this->is_Store()) {
1118     // Condition for back-to-back stores folding.
1119     return n->Opcode() == op && n->in(MemNode::Memory) == this;
1120   } else if (this->is_Load()) {
1121     // Condition for removing an unused LoadNode from the MemBarAcquire precedence input
1122     return n->Opcode() == Op_MemBarAcquire;
1123   } else if (op == Op_AddL) {
1124     // Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
1125     return n->Opcode() == Op_ConvL2I && n->in(1) == this;
1126   } else if (op == Op_SubI || op == Op_SubL) {
1127     // Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
1128     return n->Opcode() == op && n->in(2) == this;
1129   } else if (is_If() && (n->is_IfFalse() || n->is_IfTrue())) {
1130     // See IfProjNode::Identity()
1131     return true;
1132   }
1133   return false;
1134 };
1135 
1136 //--------------------------find_exact_control---------------------------------
1137 // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1138 Node* Node::find_exact_control(Node* ctrl) {
1139   if (ctrl == NULL && this->is_Region())
1140     ctrl = this->as_Region()->is_copy();
1141 

1100 // The Right Thing with def-use info.
1101 //
1102 // You cannot bury the 'this' Node inside of a graph reshape.  If the reshaped
1103 // graph uses the 'this' Node it must be the root.  If you want a Node with
1104 // the same Opcode as the 'this' pointer use 'clone'.
1105 //
1106 Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
1107   return NULL;                  // Default to being Ideal already
1108 }
1109 
1110 // Some nodes have specific Ideal subgraph transformations only if they are
1111 // unique users of specific nodes. Such nodes should be put on IGVN worklist
1112 // for the transformations to happen.
1113 bool Node::has_special_unique_user() const {
1114   assert(outcnt() == 1, "match only for unique out");
1115   Node* n = unique_out();
1116   int op  = Opcode();
1117   if (this->is_Store()) {
1118     // Condition for back-to-back stores folding.
1119     return n->Opcode() == op && n->in(MemNode::Memory) == this;
1120   } else if (this->is_Load() || this->is_DecodeN()) {
1121     // Condition for removing an unused LoadNode or DecodeNNode from the MemBarAcquire precedence input
1122     return n->Opcode() == Op_MemBarAcquire;
1123   } else if (op == Op_AddL) {
1124     // Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
1125     return n->Opcode() == Op_ConvL2I && n->in(1) == this;
1126   } else if (op == Op_SubI || op == Op_SubL) {
1127     // Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
1128     return n->Opcode() == op && n->in(2) == this;
1129   } else if (is_If() && (n->is_IfFalse() || n->is_IfTrue())) {
1130     // See IfProjNode::Identity()
1131     return true;
1132   }
1133   return false;
1134 };
1135 
1136 //--------------------------find_exact_control---------------------------------
1137 // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1138 Node* Node::find_exact_control(Node* ctrl) {
1139   if (ctrl == NULL && this->is_Region())
1140     ctrl = this->as_Region()->is_copy();
1141