diff --git a/src/share/vm/opto/cfgnode.cpp b/src/share/vm/opto/cfgnode.cpp
index 3c504710d05464592319fded0eba85de2f4eef3d..ee4ccc4dd50c3386ce233f64f20701d2877afb74 100644
--- a/src/share/vm/opto/cfgnode.cpp
+++ b/src/share/vm/opto/cfgnode.cpp
@@ -472,9 +472,7 @@ Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) {
             assert( n->req() == 2 &&  n->in(1) != NULL, "Only one data input expected" );
             // Break dead loop data path.
             // Eagerly replace phis with top to avoid phis copies generation.
-            igvn->add_users_to_worklist(n);
-            igvn->hash_delete(n); // Yank from hash before hacking edges
-            igvn->subsume_node(n, top);
+            igvn->replace_node(n, top);
             if( max != outcnt() ) {
               progress = true;
               j = refresh_out_pos(j);
@@ -518,18 +516,17 @@ Node *RegionNode::Ideal(PhaseGVN *phase, bool can_reshape) {
         igvn->hash_delete(n); // Remove from worklist before modifying edges
         if( n->is_Phi() ) {   // Collapse all Phis
           // Eagerly replace phis to avoid copies generation.
-          igvn->add_users_to_worklist(n);
-          igvn->hash_delete(n); // Yank from hash before hacking edges
+          Node* in;
           if( cnt == 0 ) {
             assert( n->req() == 1, "No data inputs expected" );
-            igvn->subsume_node(n, parent_ctrl); // replaced by top
+            in = parent_ctrl; // replaced by top
           } else {
             assert( n->req() == 2 &&  n->in(1) != NULL, "Only one data input expected" );
-            Node* in1 = n->in(1);               // replaced by unique input
-            if( n->as_Phi()->is_unsafe_data_reference(in1) )
-              in1 = phase->C->top();            // replaced by top
-            igvn->subsume_node(n, in1);
+            in = n->in(1);               // replaced by unique input
+            if( n->as_Phi()->is_unsafe_data_reference(in) )
+              in = phase->C->top();      // replaced by top
           }
+          igvn->replace_node(n, in);
         }
         else if( n->is_Region() ) { // Update all incoming edges
           assert( !igvn->eqv(n, this), "Must be removed from DefUse edges");
@@ -2127,7 +2124,7 @@ Node *NeverBranchNode::Ideal(PhaseGVN *phase, bool can_reshape) {
     // if it's not there, there's nothing to do.
     Node* fallthru = proj_out(0);
     if (fallthru != NULL) {
-      phase->is_IterGVN()->subsume_node(fallthru, in(0));
+      phase->is_IterGVN()->replace_node(fallthru, in(0));
     }
     return phase->C->top();
   }
diff --git a/src/share/vm/opto/ifnode.cpp b/src/share/vm/opto/ifnode.cpp
index 5ed25f4a9f6fb9a4b42ffb199d368f84dfd523e0..590e1379e6a323105d9ffd1c7b31492c3b0784d7 100644
--- a/src/share/vm/opto/ifnode.cpp
+++ b/src/share/vm/opto/ifnode.cpp
@@ -1081,11 +1081,9 @@ static IfNode* idealize_test(PhaseGVN* phase, IfNode* iff) {
 
   igvn->register_new_node_with_optimizer(new_if_f);
   igvn->register_new_node_with_optimizer(new_if_t);
-  igvn->hash_delete(old_if_f);
-  igvn->hash_delete(old_if_t);
   // Flip test, so flip trailing control
-  igvn->subsume_node(old_if_f, new_if_t);
-  igvn->subsume_node(old_if_t, new_if_f);
+  igvn->replace_node(old_if_f, new_if_t);
+  igvn->replace_node(old_if_t, new_if_f);
 
   // Progress
   return iff;
diff --git a/src/share/vm/opto/loopTransform.cpp b/src/share/vm/opto/loopTransform.cpp
index fb9bab44301249f7296be588c117386d5e9d1fc1..31daf7d8fef6eaba4cb6ea97aa21c44d0249bbe7 100644
--- a/src/share/vm/opto/loopTransform.cpp
+++ b/src/share/vm/opto/loopTransform.cpp
@@ -194,8 +194,7 @@ Node* IdealLoopTree::reassociate_add_sub(Node* n1, PhaseIdealLoop *phase) {
     addx = new (phase->C, 3) AddINode(x, inv);
   }
   phase->register_new_node(addx, phase->get_ctrl(x));
-  phase->_igvn.hash_delete(n1);
-  phase->_igvn.subsume_node(n1, addx);
+  phase->_igvn.replace_node(n1, addx);
   return addx;
 }
 
@@ -1586,8 +1585,7 @@ bool IdealLoopTree::policy_do_remove_empty_loop( PhaseIdealLoop *phase ) {
   Node *phi = cl->phi();
   Node *final = new (phase->C, 3) SubINode( cl->limit(), cl->stride() );
   phase->register_new_node(final,cl->in(LoopNode::EntryControl));
-  phase->_igvn.hash_delete(phi);
-  phase->_igvn.subsume_node(phi,final);
+  phase->_igvn.replace_node(phi,final);
   phase->C->set_major_progress();
   return true;
 }
diff --git a/src/share/vm/opto/loopnode.cpp b/src/share/vm/opto/loopnode.cpp
index 31bd9c6a32f61f6a27bcd8fe0a5c7615c7a7f0f9..df9224af021624c73d21c3f9ed3438609601962b 100644
--- a/src/share/vm/opto/loopnode.cpp
+++ b/src/share/vm/opto/loopnode.cpp
@@ -400,7 +400,7 @@ Node *PhaseIdealLoop::is_counted_loop( Node *x, IdealLoopTree *loop ) {
     nphi->set_req(LoopNode::LoopBackControl, phi->in(LoopNode::LoopBackControl));
     nphi = _igvn.register_new_node_with_optimizer(nphi);
     set_ctrl(nphi, get_ctrl(phi));
-    _igvn.subsume_node(phi, nphi);
+    _igvn.replace_node(phi, nphi);
     phi = nphi->as_Phi();
   }
   cmp = cmp->clone();
@@ -760,7 +760,7 @@ void IdealLoopTree::split_fall_in( PhaseIdealLoop *phase, int fall_in_cnt ) {
       // which in turn prevents removing an empty loop.
       Node *id_old_phi = old_phi->Identity( &igvn );
       if( id_old_phi != old_phi ) { // Found a simple identity?
-        // Note that I cannot call 'subsume_node' here, because
+        // Note that I cannot call 'replace_node' here, because
         // that will yank the edge from old_phi to the Region and
         // I'm mid-iteration over the Region's uses.
         for (DUIterator_Last imin, i = old_phi->last_outs(imin); i >= imin; ) {
@@ -1065,11 +1065,9 @@ bool IdealLoopTree::beautify_loops( PhaseIdealLoop *phase ) {
     l = igvn.register_new_node_with_optimizer(l, _head);
     phase->set_created_loop_node();
     // Go ahead and replace _head
-    phase->_igvn.subsume_node( _head, l );
+    phase->_igvn.replace_node( _head, l );
     _head = l;
     phase->set_loop(_head, this);
-    for (DUIterator_Fast imax, i = l->fast_outs(imax); i < imax; i++)
-      phase->_igvn.add_users_to_worklist(l->fast_out(i));
   }
 
   // Now recursively beautify nested loops
@@ -1329,8 +1327,7 @@ void IdealLoopTree::counted_loop( PhaseIdealLoop *phase ) {
         Node* add  = new (C, 3) AddINode(ratio_idx, diff);
         phase->_igvn.register_new_node_with_optimizer(add);
         phase->set_ctrl(add, cl);
-        phase->_igvn.hash_delete( phi2 );
-        phase->_igvn.subsume_node( phi2, add );
+        phase->_igvn.replace_node( phi2, add );
         // Sometimes an induction variable is unused
         if (add->outcnt() == 0) {
           phase->_igvn.remove_dead_node(add);
diff --git a/src/share/vm/opto/loopnode.hpp b/src/share/vm/opto/loopnode.hpp
index fb701084761210df5a35c525498dd6aeb629ac92..0fd4c6bbc50321fd15a0fd22630101bc24419b14 100644
--- a/src/share/vm/opto/loopnode.hpp
+++ b/src/share/vm/opto/loopnode.hpp
@@ -626,8 +626,7 @@ public:
     _nodes.map( old_node->_idx, (Node*)((intptr_t)new_node + 1) );
   }
   void lazy_replace( Node *old_node, Node *new_node ) {
-    _igvn.hash_delete(old_node);
-    _igvn.subsume_node( old_node, new_node );
+    _igvn.replace_node( old_node, new_node );
     lazy_update( old_node, new_node );
   }
   void lazy_replace_proj( Node *old_node, Node *new_node ) {
diff --git a/src/share/vm/opto/loopopts.cpp b/src/share/vm/opto/loopopts.cpp
index 4b29bc9de4f2153cacc58fcedf8ef72d5ec7bc0e..5457abec976aa7744e761a57b712ebd03e11a38a 100644
--- a/src/share/vm/opto/loopopts.cpp
+++ b/src/share/vm/opto/loopopts.cpp
@@ -354,8 +354,7 @@ Node *PhaseIdealLoop::remix_address_expressions( Node *n ) {
     register_new_node( var_scale, n_ctrl );
     Node *var_add = new (C, 3) AddINode( var_scale, inv_scale );
     register_new_node( var_add, n_ctrl );
-    _igvn.hash_delete( n );
-    _igvn.subsume_node( n, var_add );
+    _igvn.replace_node( n, var_add );
     return var_add;
   }
 
@@ -390,8 +389,7 @@ Node *PhaseIdealLoop::remix_address_expressions( Node *n ) {
           register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) );
           Node *add2 = new (C, 4) AddPNode( n->in(1), add1, n->in(2)->in(3) );
           register_new_node( add2, n_ctrl );
-          _igvn.hash_delete( n );
-          _igvn.subsume_node( n, add2 );
+          _igvn.replace_node( n, add2 );
           return add2;
         }
       }
@@ -412,8 +410,7 @@ Node *PhaseIdealLoop::remix_address_expressions( Node *n ) {
           register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) );
           Node *add2 = new (C, 4) AddPNode( n->in(1), add1, V );
           register_new_node( add2, n_ctrl );
-          _igvn.hash_delete( n );
-          _igvn.subsume_node( n, add2 );
+          _igvn.replace_node( n, add2 );
           return add2;
         }
       }
@@ -555,8 +552,7 @@ Node *PhaseIdealLoop::conditional_move( Node *region ) {
     }
     Node *cmov = CMoveNode::make( C, cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi) );
     register_new_node( cmov, cmov_ctrl );
-    _igvn.hash_delete(phi);
-    _igvn.subsume_node( phi, cmov );
+    _igvn.replace_node( phi, cmov );
 #ifndef PRODUCT
     if( VerifyLoopOptimizations ) verify();
 #endif
@@ -642,8 +638,7 @@ Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) {
 
   // Found a Phi to split thru!
   // Replace 'n' with the new phi
-  _igvn.hash_delete(n);
-  _igvn.subsume_node( n, phi );
+  _igvn.replace_node( n, phi );
   // Moved a load around the loop, 'en-registering' something.
   if( n_blk->Opcode() == Op_Loop && n->is_Load() &&
       !phi->in(LoopNode::LoopBackControl)->is_Load() )
@@ -789,13 +784,11 @@ void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) {
 
     // Found a Phi to split thru!
     // Replace 'n' with the new phi
-    _igvn.hash_delete(n);
-    _igvn.subsume_node( n, phi );
+    _igvn.replace_node( n, phi );
 
     // Now split the bool up thru the phi
     Node *bolphi = split_thru_phi( bol, n_ctrl, -1 );
-    _igvn.hash_delete(bol);
-    _igvn.subsume_node( bol, bolphi );
+    _igvn.replace_node( bol, bolphi );
     assert( iff->in(1) == bolphi, "" );
     if( bolphi->Value(&_igvn)->singleton() )
       return;
@@ -803,8 +796,7 @@ void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) {
     // Conditional-move?  Must split up now
     if( !iff->is_If() ) {
       Node *cmovphi = split_thru_phi( iff, n_ctrl, -1 );
-      _igvn.hash_delete(iff);
-      _igvn.subsume_node( iff, cmovphi );
+      _igvn.replace_node( iff, cmovphi );
       return;
     }
 
@@ -950,9 +942,7 @@ void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) {
   if( n_op == Op_Opaque2 &&
       n->in(1) != NULL &&
       get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) {
-    _igvn.add_users_to_worklist(n);
-    _igvn.hash_delete(n);
-    _igvn.subsume_node( n, n->in(1) );
+    _igvn.replace_node( n, n->in(1) );
   }
 }
 
@@ -1425,7 +1415,7 @@ void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd
           // IGVN does CSE).
           Node *hit = _igvn.hash_find_insert(use);
           if( hit )             // Go ahead and re-hash for hits.
-            _igvn.subsume_node( use, hit );
+            _igvn.replace_node( use, hit );
         }
 
         // If 'use' was in the loop-exit block, it now needs to be sunk
diff --git a/src/share/vm/opto/macro.cpp b/src/share/vm/opto/macro.cpp
index 4760659b5a1747ad0eddf7a7e0bbbb5f34b48b36..3431731674de5a5431d3810d2873ff3ccf4bc4b2 100644
--- a/src/share/vm/opto/macro.cpp
+++ b/src/share/vm/opto/macro.cpp
@@ -135,8 +135,7 @@ CallNode* PhaseMacroExpand::make_slow_call(CallNode *oldcall, const TypeFunc* sl
   if (parm1 != NULL)  call->init_req(TypeFunc::Parms+1, parm1);
   copy_call_debug_info(oldcall, call);
   call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
-  _igvn.hash_delete(oldcall);
-  _igvn.subsume_node(oldcall, call);
+  _igvn.replace_node(oldcall, call);
   transform_later(call);
 
   return call;
@@ -523,8 +522,7 @@ Node *PhaseMacroExpand::value_from_mem(Node *sfpt_mem, BasicType ft, const Type
         // Kill all new Phis
         while(value_phis.is_nonempty()) {
           Node* n = value_phis.node();
-          _igvn.hash_delete(n);
-          _igvn.subsume_node(n, C->top());
+          _igvn.replace_node(n, C->top());
           value_phis.pop();
         }
       }
@@ -1311,8 +1309,7 @@ void PhaseMacroExpand::expand_allocate_common(
   if (!always_slow) {
     call->set_cnt(PROB_UNLIKELY_MAG(4));  // Same effect as RC_UNCOMMON.
   }
-  _igvn.hash_delete(alloc);
-  _igvn.subsume_node(alloc, call);
+  _igvn.replace_node(alloc, call);
   transform_later(call);
 
   // Identify the output projections from the allocate node and
diff --git a/src/share/vm/opto/phaseX.cpp b/src/share/vm/opto/phaseX.cpp
index 657a413827e9ed1b04735f8a4ad2b4da136dd7e3..590bbd0adae537cad243d0291b644530abdee618 100644
--- a/src/share/vm/opto/phaseX.cpp
+++ b/src/share/vm/opto/phaseX.cpp
@@ -1447,16 +1447,12 @@ Node *PhaseCCP::transform_once( Node *n ) {
           Node* m = n->out(i);
           if( m->is_Phi() ) {
             assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
-            add_users_to_worklist(m);
-            hash_delete(m); // Yank from hash before hacking edges
-            subsume_node(m, nn);
+            replace_node(m, nn);
             --i; // deleted this phi; rescan starting with next position
           }
         }
       }
-      add_users_to_worklist(n); // Users of about-to-be-constant 'n'
-      hash_delete(n);           // Removed 'n' from table before subsuming it
-      subsume_node(n,nn);       // Update DefUse edges for new constant
+      replace_node(n,nn);       // Update DefUse edges for new constant
     }
     return nn;
   }
diff --git a/src/share/vm/opto/phaseX.hpp b/src/share/vm/opto/phaseX.hpp
index 9f1b419416e5d0198b9018d34a427ec093d9d86b..9a4535cb208b987e8f0da6c51892db1a2c294a77 100644
--- a/src/share/vm/opto/phaseX.hpp
+++ b/src/share/vm/opto/phaseX.hpp
@@ -393,6 +393,10 @@ class PhaseIterGVN : public PhaseGVN {
 
   // Idealize old Node 'n' with respect to its inputs and its value
   virtual Node *transform_old( Node *a_node );
+
+  // Subsume users of node 'old' into node 'nn'
+  void subsume_node( Node *old, Node *nn );
+
 protected:
 
   // Idealize new Node 'n' with respect to its inputs and its value
@@ -439,10 +443,6 @@ public:
     remove_globally_dead_node(dead);
   }
 
-  // Subsume users of node 'old' into node 'nn'
-  // If no Def-Use info existed for 'nn' it will after call.
-  void subsume_node( Node *old, Node *nn );
-
   // Add users of 'n' to worklist
   void add_users_to_worklist0( Node *n );
   void add_users_to_worklist ( Node *n );
@@ -450,7 +450,7 @@ public:
   // Replace old node with new one.
   void replace_node( Node *old, Node *nn ) {
     add_users_to_worklist(old);
-    hash_delete(old);
+    hash_delete(old); // Yank from hash before hacking edges
     subsume_node(old, nn);
   }
 
diff --git a/src/share/vm/opto/split_if.cpp b/src/share/vm/opto/split_if.cpp
index 57d2f3a740a7dfc7c37c4ed0ca3100ffd46db526..3008ac75a5d5ff8f6ec97128020e0696b22a31a8 100644
--- a/src/share/vm/opto/split_if.cpp
+++ b/src/share/vm/opto/split_if.cpp
@@ -217,8 +217,7 @@ bool PhaseIdealLoop::split_up( Node *n, Node *blk1, Node *blk2 ) {
   register_new_node(phi, blk1);
 
   // Remove cloned-up value from optimizer; use phi instead
-  _igvn.hash_delete(n);
-  _igvn.subsume_node( n, phi );
+  _igvn.replace_node( n, phi );
 
   // (There used to be a self-recursive call to split_up() here,
   // but it is not needed.  All necessary forward walking is done
@@ -352,8 +351,7 @@ Node *PhaseIdealLoop::find_use_block( Node *use, Node *def, Node *old_false, Nod
   }
 
   if (use_blk == NULL) {        // He's dead, Jim
-    _igvn.hash_delete(use);
-    _igvn.subsume_node(use, C->top());
+    _igvn.replace_node(use, C->top());
   }
 
   return use_blk;
diff --git a/src/share/vm/opto/superword.cpp b/src/share/vm/opto/superword.cpp
index be93c15ea8b5fbb7bfec1f5373f8194b6200cefb..fcb8f927fdba09b095c798ef7d2e57864d1f520e 100644
--- a/src/share/vm/opto/superword.cpp
+++ b/src/share/vm/opto/superword.cpp
@@ -1172,8 +1172,7 @@ void SuperWord::output() {
       _phase->set_ctrl(vn, _phase->get_ctrl(p->at(0)));
       for (uint j = 0; j < p->size(); j++) {
         Node* pm = p->at(j);
-        _igvn.hash_delete(pm);
-        _igvn.subsume_node(pm, vn);
+        _igvn.replace_node(pm, vn);
       }
       _igvn._worklist.push(vn);
     }