8004640: C2 assert failure in memnode.cpp: NULL+offs not RAW address

Summary: always transform AddP nodes in IdealKit by calling _gvn.transform().
Reviewed-by: roland, twisti

src/share/vm/opto/graphKit.cpp

@@ -3445,7 +3445,6 @@ void GraphKit::sync_kit(IdealKit& ideal) {
 
 void GraphKit::final_sync(IdealKit& ideal) {
   // Final sync IdealKit and graphKit.
-  __ drain_delay_transform();
   sync_kit(ideal);
 }
 

src/share/vm/opto/idealKit.cpp

@@ -48,9 +48,9 @@ IdealKit::IdealKit(GraphKit* gkit, bool delay_all_transforms, bool has_declarati
   _cvstate = NULL;
   // We can go memory state free or else we need the entire memory state
   assert(_initial_memory == NULL || _initial_memory->Opcode() == Op_MergeMem, "memory must be pre-split");
+  assert(!_gvn.is_IterGVN(), "IdealKit can't be used during Optimize phase");
   int init_size = 5;
   _pending_cvstates = new (C->node_arena()) GrowableArray<Node*>(C->node_arena(), init_size, 0, 0);
-  _delay_transform  = new (C->node_arena()) GrowableArray<Node*>(C->node_arena(), init_size, 0, 0);
   DEBUG_ONLY(_state = new (C->node_arena()) GrowableArray<int>(C->node_arena(), init_size, 0, 0));
   if (!has_declarations) {
      declarations_done();
@@ -296,19 +296,16 @@ Node* IdealKit::transform(Node* n) {
     return delay_transform(n);
   } else {
     n = gvn().transform(n);
-    if (!gvn().is_IterGVN()) {
-      C->record_for_igvn(n);
-    }
+    C->record_for_igvn(n);
     return n;
   }
 }
 
 //-----------------------------delay_transform-----------------------------------
 Node* IdealKit::delay_transform(Node* n) {
-  if (!gvn().is_IterGVN() || !gvn().is_IterGVN()->delay_transform()) {
-    gvn().set_type(n, n->bottom_type());
-  }
-  _delay_transform->push(n);
+  // Delay transform until IterativeGVN
+  gvn().set_type(n, n->bottom_type());
+  C->record_for_igvn(n);
   return n;
 }
 
@@ -332,17 +329,6 @@ void IdealKit::clear(Node* m) {
   for (uint i = 0; i < m->req(); i++) m->set_req(i, NULL);
 }
 
-//-----------------------------drain_delay_transform----------------------------
-void IdealKit::drain_delay_transform() {
-  while (_delay_transform->length() > 0) {
-    Node* n = _delay_transform->pop();
-    gvn().transform(n);
-    if (!gvn().is_IterGVN()) {
-      C->record_for_igvn(n);
-    }
-  }
-}
-
 //-----------------------------IdealVariable----------------------------
 IdealVariable::IdealVariable(IdealKit &k) {
   k.declare(this);
@@ -351,9 +337,7 @@ IdealVariable::IdealVariable(IdealKit &k) {
 Node* IdealKit::memory(uint alias_idx) {
   MergeMemNode* mem = merged_memory();
   Node* p = mem->memory_at(alias_idx);
-  if (!gvn().is_IterGVN() || !gvn().is_IterGVN()->delay_transform()) {
-    _gvn.set_type(p, Type::MEMORY);  // must be mapped
-  }
+  _gvn.set_type(p, Type::MEMORY);  // must be mapped
   return p;
 }
 

src/share/vm/opto/idealKit.hpp

@@ -102,7 +102,6 @@ class IdealKit: public StackObj {
   Compile * const C;
   PhaseGVN &_gvn;
   GrowableArray<Node*>* _pending_cvstates; // stack of cvstates
-  GrowableArray<Node*>* _delay_transform;  // delay invoking gvn.transform until drain
   Node* _cvstate;                          // current cvstate (control, memory and variables)
   uint _var_ct;                            // number of variables
   bool _delay_all_transforms;              // flag forcing all transforms to be delayed
@@ -121,7 +120,7 @@ class IdealKit: public StackObj {
   void clear(Node* m);                     // clear a cvstate
   void stop() { clear(_cvstate); }         // clear current cvstate
   Node* delay_transform(Node* n);
-  Node* transform(Node* n);                // gvn.transform or push node on delay list
+  Node* transform(Node* n);                // gvn.transform or skip it
   Node* promote_to_phi(Node* n, Node* reg);// Promote "n" to a phi on region "reg"
   bool was_promoted_to_phi(Node* n, Node* reg) {
     return (n->is_Phi() && n->in(0) == reg);
@@ -146,7 +145,6 @@ class IdealKit: public StackObj {
   IdealKit(GraphKit* gkit, bool delay_all_transforms = false, bool has_declarations = false);
   ~IdealKit() {
     stop();
-    drain_delay_transform();
   }
   void sync_kit(GraphKit* gkit);
 
@@ -173,7 +171,6 @@ class IdealKit: public StackObj {
   void bind(Node* lab);
   void goto_(Node* lab, bool bind = false);
   void declarations_done();
-  void drain_delay_transform();
 
   Node* IfTrue(IfNode* iff)  { return transform(new (C) IfTrueNode(iff)); }
   Node* IfFalse(IfNode* iff) { return transform(new (C) IfFalseNode(iff)); }
@@ -198,7 +195,11 @@ class IdealKit: public StackObj {
   Node* thread()  {  return gvn().transform(new (C) ThreadLocalNode()); }
 
   // Pointers
-  Node* AddP(Node *base, Node *ptr, Node *off) { return transform(new (C) AddPNode(base, ptr, off)); }
+
+  // Raw address should be transformed regardless 'delay_transform' flag
+  // to produce canonical form CastX2P(offset).
+  Node* AddP(Node *base, Node *ptr, Node *off) { return _gvn.transform(new (C) AddPNode(base, ptr, off)); }
+
   Node* CmpP(Node* l, Node* r) { return transform(new (C) CmpPNode(l, r)); }
 #ifdef _LP64
   Node* XorX(Node* l, Node* r) { return transform(new (C) XorLNode(l, r)); }
@@ -208,8 +209,6 @@ class IdealKit: public StackObj {
   Node* URShiftX(Node* l, Node* r) { return transform(new (C) URShiftXNode(l, r)); }
   Node* ConX(jint k) { return (Node*)gvn().MakeConX(k); }
   Node* CastPX(Node* ctl, Node* p) { return transform(new (C) CastP2XNode(ctl, p)); }
-  // Add a fixed offset to a pointer
-  Node* basic_plus_adr(Node* base, Node* ptr, intptr_t offset);
 
   // Memory operations
 

src/share/vm/opto/loopnode.cpp

@@ -2251,6 +2251,11 @@ void PhaseIdealLoop::build_and_optimize(bool do_split_ifs, bool skip_loop_opts)
     return;
   }
 
+  // clear out the dead code after build_loop_late
+  while (_deadlist.size()) {
+    _igvn.remove_globally_dead_node(_deadlist.pop());
+  }
+
   if (stop_early) {
     assert(do_expensive_nodes, "why are we here?");
     if (process_expensive_nodes()) {
@@ -2260,9 +2265,7 @@ void PhaseIdealLoop::build_and_optimize(bool do_split_ifs, bool skip_loop_opts)
       // nodes again.
       C->set_major_progress();
     }
-
     _igvn.optimize();
-
     return;
   }
 
@@ -2273,11 +2276,6 @@ void PhaseIdealLoop::build_and_optimize(bool do_split_ifs, bool skip_loop_opts)
     eliminate_useless_predicates();
   }
 
-  // clear out the dead code
-  while(_deadlist.size()) {
-    _igvn.remove_globally_dead_node(_deadlist.pop());
-  }
-
 #ifndef PRODUCT
   C->verify_graph_edges();
   if (_verify_me) {             // Nested verify pass?

src/share/vm/opto/phaseX.cpp

@@ -1166,31 +1166,30 @@ void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
     if (progress_state == PROCESS_INPUTS) {
       // After following inputs, continue to outputs
       _stack.set_index(PROCESS_OUTPUTS);
-      // Remove from iterative worklist
-      _worklist.remove(dead);
       if (!dead->is_Con()) { // Don't kill cons but uses
         bool recurse = false;
         // Remove from hash table
         _table.hash_delete( dead );
         // Smash all inputs to 'dead', isolating him completely
-        for( uint i = 0; i < dead->req(); i++ ) {
+        for (uint i = 0; i < dead->req(); i++) {
           Node *in = dead->in(i);
-          if( in ) {                 // Points to something?
-            dead->set_req(i,NULL);  // Kill the edge
-            if (in->outcnt() == 0 && in != C->top()) {// Made input go dead?
+          if (in != NULL && in != C->top()) {  // Points to something?
+            int nrep = dead->replace_edge(in, NULL);  // Kill edges
+            assert((nrep > 0), "sanity");
+            if (in->outcnt() == 0) { // Made input go dead?
               _stack.push(in, PROCESS_INPUTS); // Recursively remove
               recurse = true;
             } else if (in->outcnt() == 1 &&
                        in->has_special_unique_user()) {
               _worklist.push(in->unique_out());
             } else if (in->outcnt() <= 2 && dead->is_Phi()) {
-              if( in->Opcode() == Op_Region )
+              if (in->Opcode() == Op_Region) {
                 _worklist.push(in);
-              else if( in->is_Store() ) {
+              } else if (in->is_Store()) {
                 DUIterator_Fast imax, i = in->fast_outs(imax);
                 _worklist.push(in->fast_out(i));
                 i++;
-                if(in->outcnt() == 2) {
+                if (in->outcnt() == 2) {
                   _worklist.push(in->fast_out(i));
                   i++;
                 }
@@ -1209,38 +1208,42 @@ void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
                 }
               }
             }
-          }
-        }
-        C->record_dead_node(dead->_idx);
-        if (dead->is_macro()) {
-          C->remove_macro_node(dead);
-        }
-        if (dead->is_expensive()) {
-          C->remove_expensive_node(dead);
-        }
-
+          } // if (in != NULL && in != C->top())
+        } // for (uint i = 0; i < dead->req(); i++)
         if (recurse) {
           continue;
         }
-      }
-      // Constant node that has no out-edges and has only one in-edge from
-      // root is usually dead. However, sometimes reshaping walk makes
-      // it reachable by adding use edges. So, we will NOT count Con nodes
-      // as dead to be conservative about the dead node count at any
-      // given time.
-    }
+      } // if (!dead->is_Con())
+    } // if (progress_state == PROCESS_INPUTS)
 
     // Aggressively kill globally dead uses
     // (Rather than pushing all the outs at once, we push one at a time,
     // plus the parent to resume later, because of the indefinite number
     // of edge deletions per loop trip.)
     if (dead->outcnt() > 0) {
-      // Recursively remove
+      // Recursively remove output edges
       _stack.push(dead->raw_out(0), PROCESS_INPUTS);
     } else {
+      // Finished disconnecting all input and output edges.
       _stack.pop();
+      // Remove dead node from iterative worklist
+      _worklist.remove(dead);
+      // Constant node that has no out-edges and has only one in-edge from
+      // root is usually dead. However, sometimes reshaping walk makes
+      // it reachable by adding use edges. So, we will NOT count Con nodes
+      // as dead to be conservative about the dead node count at any
+      // given time.
+      if (!dead->is_Con()) {
+        C->record_dead_node(dead->_idx);
+      }
+      if (dead->is_macro()) {
+        C->remove_macro_node(dead);
+      }
+      if (dead->is_expensive()) {
+        C->remove_expensive_node(dead);
+      }
     }
-  }
+  } // while (_stack.is_nonempty())
 }
 
 //------------------------------subsume_node-----------------------------------