8066312: Add new Node* Node::find_out(int opc) method

Added methods find_user_with() and has_user_with() for searching for a particular out type.

Reviewed-by: kvn, jrose

hotspot/src/share/vm/opto/escape.cpp

@@ -2010,14 +2010,9 @@ bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
         bt = field->layout_type();
       } else {
         // Check for unsafe oop field access
-        for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
-          int opcode = n->fast_out(i)->Opcode();
-          if (opcode == Op_StoreP || opcode == Op_LoadP ||
-              opcode == Op_StoreN || opcode == Op_LoadN) {
-            bt = T_OBJECT;
-            (*unsafe) = true;
-            break;
-          }
+        if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
+          bt = T_OBJECT;
+          (*unsafe) = true;
         }
       }
     } else if (adr_type->isa_aryptr()) {
@@ -2031,13 +2026,8 @@ bool ConnectionGraph::is_oop_field(Node* n, int offset, bool* unsafe) {
       }
     } else if (adr_type->isa_rawptr() || adr_type->isa_klassptr()) {
       // Allocation initialization, ThreadLocal field access, unsafe access
-      for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
-        int opcode = n->fast_out(i)->Opcode();
-        if (opcode == Op_StoreP || opcode == Op_LoadP ||
-            opcode == Op_StoreN || opcode == Op_LoadN) {
-          bt = T_OBJECT;
-          break;
-        }
+      if (n->has_out_with(Op_StoreP, Op_LoadP, Op_StoreN, Op_LoadN)) {
+        bt = T_OBJECT;
       }
     }
   }
@@ -3092,13 +3082,7 @@ void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist)
         continue;
     } else if (n->Opcode() == Op_EncodeISOArray) {
       // get the memory projection
-      for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
-        Node *use = n->fast_out(i);
-        if (use->Opcode() == Op_SCMemProj) {
-          n = use;
-          break;
-        }
-      }
+      n = n->find_out_with(Op_SCMemProj);
       assert(n->Opcode() == Op_SCMemProj, "memory projection required");
     } else {
       assert(n->is_Mem(), "memory node required.");
@@ -3122,13 +3106,7 @@ void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist)
         continue;  // don't push users
       } else if (n->is_LoadStore()) {
         // get the memory projection
-        for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
-          Node *use = n->fast_out(i);
-          if (use->Opcode() == Op_SCMemProj) {
-            n = use;
-            break;
-          }
-        }
+        n = n->find_out_with(Op_SCMemProj);
         assert(n->Opcode() == Op_SCMemProj, "memory projection required");
       }
     }

hotspot/src/share/vm/opto/ifg.cpp

@@ -535,12 +535,8 @@ bool PhaseChaitin::remove_node_if_not_used(Block* b, uint location, Node* n, uin
       // The method add_input_to_liveout() keeps such nodes alive (put them on liveout list)
       // when it sees SCMemProj node in a block. Unfortunately SCMemProj node could be placed
       // in block in such order that KILL MachProj nodes are processed first.
-      uint cnt = def->outcnt();
-      for (uint i = 0; i < cnt; i++) {
-        Node* proj = def->raw_out(i);
-        if (proj->Opcode() == Op_SCMemProj) {
-          return false;
-        }
+      if (def->has_out_with(Op_SCMemProj)) {
+        return false;
       }
     }
     b->remove_node(location);

hotspot/src/share/vm/opto/macro.cpp

@@ -258,14 +258,7 @@ void PhaseMacroExpand::eliminate_card_mark(Node* p2x) {
     // Search for CastP2X->Xor->URShift->Cmp path which
     // checks if the store done to a different from the value's region.
     // And replace Cmp with #0 (false) to collapse G1 post barrier.
-    Node* xorx = NULL;
-    for (DUIterator_Fast imax, i = p2x->fast_outs(imax); i < imax; i++) {
-      Node* u = p2x->fast_out(i);
-      if (u->Opcode() == Op_XorX) {
-        xorx = u;
-        break;
-      }
-    }
+    Node* xorx = p2x->find_out_with(Op_XorX);
     assert(xorx != NULL, "missing G1 post barrier");
     Node* shift = xorx->unique_out();
     Node* cmpx = shift->unique_out();

hotspot/src/share/vm/opto/memnode.cpp

@@ -2609,7 +2609,6 @@ bool StoreNode::value_never_loaded( PhaseTransform *phase) const {
     return false; // if not a distinct instance, there may be aliases of the address
   for (DUIterator_Fast imax, i = adr->fast_outs(imax); i < imax; i++) {
     Node *use = adr->fast_out(i);
-    int opc = use->Opcode();
     if (use->is_Load() || use->is_LoadStore()) {
       return false;
     }

hotspot/src/share/vm/opto/node.cpp

@@ -881,6 +881,34 @@ Node* Node::uncast() const {
     return (Node*) this;
 }
 
+// Find out of current node that matches opcode.
+Node* Node::find_out_with(int opcode) {
+  for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
+    Node* use = fast_out(i);
+    if (use->Opcode() == opcode) {
+      return use;
+    }
+  }
+  return NULL;
+}
+
+// Return true if the current node has an out that matches opcode.
+bool Node::has_out_with(int opcode) {
+  return (find_out_with(opcode) != NULL);
+}
+
+// Return true if the current node has an out that matches any of the opcodes.
+bool Node::has_out_with(int opcode1, int opcode2, int opcode3, int opcode4) {
+  for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
+      int opcode = fast_out(i)->Opcode();
+      if (opcode == opcode1 || opcode == opcode2 || opcode == opcode3 || opcode == opcode4) {
+        return true;
+      }
+  }
+  return false;
+}
+
+
 //---------------------------uncast_helper-------------------------------------
 Node* Node::uncast_helper(const Node* p) {
 #ifdef ASSERT

hotspot/src/share/vm/opto/node.hpp

@@ -436,6 +436,13 @@ protected:
     return (this->uncast() == n->uncast());
   }
 
+  // Find out of current node that matches opcode.
+  Node* find_out_with(int opcode);
+  // Return true if the current node has an out that matches opcode.
+  bool has_out_with(int opcode);
+  // Return true if the current node has an out that matches any of the opcodes.
+  bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
+
 private:
   static Node* uncast_helper(const Node* n);
 
@@ -507,18 +514,25 @@ public:
 
 //----------------- Other Node Properties
 
-  // Generate class id for some ideal nodes to avoid virtual query
-  // methods is_<Node>().
-  // Class id is the set of bits corresponded to the node class and all its
-  // super classes so that queries for super classes are also valid.
-  // Subclasses of the same super class have different assigned bit
-  // (the third parameter in the macro DEFINE_CLASS_ID).
-  // Classes with deeper hierarchy are declared first.
-  // Classes with the same hierarchy depth are sorted by usage frequency.
+  // Generate class IDs for (some) ideal nodes so that it is possible to determine
+  // the type of a node using a non-virtual method call (the method is_<Node>() below).
   //
-  // The query method masks the bits to cut off bits of subclasses
-  // and then compare the result with the class id
-  // (see the macro DEFINE_CLASS_QUERY below).
+  // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
+  // the type of the node the ID represents; another subset of an ID's bits are reserved
+  // for the superclasses of the node represented by the ID.
+  //
+  // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
+  // returns false. A.is_A() returns true.
+  //
+  // If two classes, A and B, have the same superclass, a different bit of A's class id
+  // is reserved for A's type than for B's type. That bit is specified by the third
+  // parameter in the macro DEFINE_CLASS_ID.
+  //
+  // By convention, classes with deeper hierarchy are declared first. Moreover,
+  // classes with the same hierarchy depth are sorted by usage frequency.
+  //
+  // The query method masks the bits to cut off bits of subclasses and then compares
+  // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
   //
   //  Class_MachCall=30, ClassMask_MachCall=31
   // 12               8               4               0