7026700: regression in 6u24-rev-b23: Crash in C2 compiler in PhaseIdealLoop::build_loop_late_post

Summary: memory slices should be always created for non-static fields after allocation
Reviewed-by: never

src/share/vm/opto/escape.cpp

@@ -1437,7 +1437,10 @@ void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist)
 
   // Update the memory inputs of MemNodes with the value we computed
   // in Phase 2 and move stores memory users to corresponding memory slices.
-#ifdef ASSERT
+
+  // Disable memory split verification code until the fix for 6984348.
+  // Currently it produces false negative results since it does not cover all cases.
+#if 0 // ifdef ASSERT
   visited.Reset();
   Node_Stack old_mems(arena, _compile->unique() >> 2);
 #endif
@@ -1447,7 +1450,7 @@ void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist)
       Node *n = ptnode_adr(i)->_node;
       assert(n != NULL, "sanity");
       if (n->is_Mem()) {
-#ifdef ASSERT
+#if 0 // ifdef ASSERT
         Node* old_mem = n->in(MemNode::Memory);
         if (!visited.test_set(old_mem->_idx)) {
           old_mems.push(old_mem, old_mem->outcnt());
@@ -1469,13 +1472,13 @@ void ConnectionGraph::split_unique_types(GrowableArray<Node *>  &alloc_worklist)
       }
     }
   }
-#ifdef ASSERT
+#if 0 // ifdef ASSERT
   // Verify that memory was split correctly
   while (old_mems.is_nonempty()) {
     Node* old_mem = old_mems.node();
     uint  old_cnt = old_mems.index();
     old_mems.pop();
-    assert(old_cnt = old_mem->outcnt(), "old mem could be lost");
+    assert(old_cnt == old_mem->outcnt(), "old mem could be lost");
   }
 #endif
 }

src/share/vm/opto/graphKit.cpp

@@ -2950,8 +2950,7 @@ static void hook_memory_on_init(GraphKit& kit, int alias_idx,
 
 //---------------------------set_output_for_allocation-------------------------
 Node* GraphKit::set_output_for_allocation(AllocateNode* alloc,
-                                          const TypeOopPtr* oop_type,
-                                          bool raw_mem_only) {
+                                          const TypeOopPtr* oop_type) {
   int rawidx = Compile::AliasIdxRaw;
   alloc->set_req( TypeFunc::FramePtr, frameptr() );
   add_safepoint_edges(alloc);
@@ -2975,7 +2974,7 @@ Node* GraphKit::set_output_for_allocation(AllocateNode* alloc,
                                                  rawoop)->as_Initialize();
   assert(alloc->initialization() == init,  "2-way macro link must work");
   assert(init ->allocation()     == alloc, "2-way macro link must work");
-  if (ReduceFieldZeroing && !raw_mem_only) {
+  {
     // Extract memory strands which may participate in the new object's
     // initialization, and source them from the new InitializeNode.
     // This will allow us to observe initializations when they occur,
@@ -3036,11 +3035,9 @@ Node* GraphKit::set_output_for_allocation(AllocateNode* alloc,
 // the type to a constant.
 // The optional arguments are for specialized use by intrinsics:
 //  - If 'extra_slow_test' if not null is an extra condition for the slow-path.
-//  - If 'raw_mem_only', do not cast the result to an oop.
 //  - If 'return_size_val', report the the total object size to the caller.
 Node* GraphKit::new_instance(Node* klass_node,
                              Node* extra_slow_test,
-                             bool raw_mem_only, // affect only raw memory
                              Node* *return_size_val) {
   // Compute size in doublewords
   // The size is always an integral number of doublewords, represented
@@ -3111,7 +3108,7 @@ Node* GraphKit::new_instance(Node* klass_node,
                      size, klass_node,
                      initial_slow_test);
 
-  return set_output_for_allocation(alloc, oop_type, raw_mem_only);
+  return set_output_for_allocation(alloc, oop_type);
 }
 
 //-------------------------------new_array-------------------------------------
@@ -3121,7 +3118,6 @@ Node* GraphKit::new_instance(Node* klass_node,
 Node* GraphKit::new_array(Node* klass_node,     // array klass (maybe variable)
                           Node* length,         // number of array elements
                           int   nargs,          // number of arguments to push back for uncommon trap
-                          bool raw_mem_only,    // affect only raw memory
                           Node* *return_size_val) {
   jint  layout_con = Klass::_lh_neutral_value;
   Node* layout_val = get_layout_helper(klass_node, layout_con);
@@ -3266,7 +3262,7 @@ Node* GraphKit::new_array(Node* klass_node,     // array klass (maybe variable)
     ary_type = ary_type->is_aryptr()->cast_to_size(length_type);
   }
 
-  Node* javaoop = set_output_for_allocation(alloc, ary_type, raw_mem_only);
+  Node* javaoop = set_output_for_allocation(alloc, ary_type);
 
   // Cast length on remaining path to be as narrow as possible
   if (map()->find_edge(length) >= 0) {

src/share/vm/opto/graphKit.hpp

@@ -769,15 +769,13 @@ class GraphKit : public Phase {
 
   // implementation of object creation
   Node* set_output_for_allocation(AllocateNode* alloc,
-                                  const TypeOopPtr* oop_type,
-                                  bool raw_mem_only);
+                                  const TypeOopPtr* oop_type);
   Node* get_layout_helper(Node* klass_node, jint& constant_value);
   Node* new_instance(Node* klass_node,
                      Node* slow_test = NULL,
-                     bool raw_mem_only = false,
                      Node* *return_size_val = NULL);
   Node* new_array(Node* klass_node, Node* count_val, int nargs,
-                  bool raw_mem_only = false, Node* *return_size_val = NULL);
+                  Node* *return_size_val = NULL);
 
   // Handy for making control flow
   IfNode* create_and_map_if(Node* ctrl, Node* tst, float prob, float cnt) {

src/share/vm/opto/library_call.cpp

@@ -3376,8 +3376,7 @@ bool LibraryCallKit::inline_array_copyOf(bool is_copyOfRange) {
       Node* orig_tail = _gvn.transform( new(C, 3) SubINode(orig_length, start) );
       Node* moved = generate_min_max(vmIntrinsics::_min, orig_tail, length);
 
-      const bool raw_mem_only = true;
-      newcopy = new_array(klass_node, length, 0, raw_mem_only);
+      newcopy = new_array(klass_node, length, 0);
 
       // Generate a direct call to the right arraycopy function(s).
       // We know the copy is disjoint but we might not know if the
@@ -4174,8 +4173,6 @@ bool LibraryCallKit::inline_native_clone(bool is_virtual) {
 
     const TypePtr* raw_adr_type = TypeRawPtr::BOTTOM;
     int raw_adr_idx = Compile::AliasIdxRaw;
-    const bool raw_mem_only = true;
-
 
     Node* array_ctl = generate_array_guard(obj_klass, (RegionNode*)NULL);
     if (array_ctl != NULL) {
@@ -4184,8 +4181,7 @@ bool LibraryCallKit::inline_native_clone(bool is_virtual) {
       set_control(array_ctl);
       Node* obj_length = load_array_length(obj);
       Node* obj_size  = NULL;
-      Node* alloc_obj = new_array(obj_klass, obj_length, 0,
-                                  raw_mem_only, &obj_size);
+      Node* alloc_obj = new_array(obj_klass, obj_length, 0, &obj_size);
 
       if (!use_ReduceInitialCardMarks()) {
         // If it is an oop array, it requires very special treatment,
@@ -4257,7 +4253,7 @@ bool LibraryCallKit::inline_native_clone(bool is_virtual) {
       // It's an instance, and it passed the slow-path tests.
       PreserveJVMState pjvms(this);
       Node* obj_size  = NULL;
-      Node* alloc_obj = new_instance(obj_klass, NULL, raw_mem_only, &obj_size);
+      Node* alloc_obj = new_instance(obj_klass, NULL, &obj_size);
 
       copy_to_clone(obj, alloc_obj, obj_size, false, !use_ReduceInitialCardMarks());
 

src/share/vm/opto/memnode.cpp

@@ -1259,15 +1259,18 @@ Node *LoadNode::split_through_phi(PhaseGVN *phase) {
     return NULL; // Wait stable graph
   }
   uint cnt = mem->req();
-  for( uint i = 1; i < cnt; i++ ) {
+  for (uint i = 1; i < cnt; i++) {
+    Node* rc = region->in(i);
+    if (rc == NULL || phase->type(rc) == Type::TOP)
+      return NULL; // Wait stable graph
     Node *in = mem->in(i);
-    if( in == NULL ) {
+    if (in == NULL) {
       return NULL; // Wait stable graph
     }
   }
   // Check for loop invariant.
   if (cnt == 3) {
-    for( uint i = 1; i < cnt; i++ ) {
+    for (uint i = 1; i < cnt; i++) {
       Node *in = mem->in(i);
       Node* m = MemNode::optimize_memory_chain(in, addr_t, phase);
       if (m == mem) {
@@ -1281,38 +1284,37 @@ Node *LoadNode::split_through_phi(PhaseGVN *phase) {
 
   // Do nothing here if Identity will find a value
   // (to avoid infinite chain of value phis generation).
-  if ( !phase->eqv(this, this->Identity(phase)) )
+  if (!phase->eqv(this, this->Identity(phase)))
     return NULL;
 
   // Skip the split if the region dominates some control edge of the address.
-  if (cnt == 3 && !MemNode::all_controls_dominate(address, region))
+  if (!MemNode::all_controls_dominate(address, region))
     return NULL;
 
   const Type* this_type = this->bottom_type();
   int this_index  = phase->C->get_alias_index(addr_t);
   int this_offset = addr_t->offset();
   int this_iid    = addr_t->is_oopptr()->instance_id();
-  int wins = 0;
   PhaseIterGVN *igvn = phase->is_IterGVN();
   Node *phi = new (igvn->C, region->req()) PhiNode(region, this_type, NULL, this_iid, this_index, this_offset);
-  for( uint i = 1; i < region->req(); i++ ) {
+  for (uint i = 1; i < region->req(); i++) {
     Node *x;
     Node* the_clone = NULL;
-    if( region->in(i) == phase->C->top() ) {
+    if (region->in(i) == phase->C->top()) {
       x = phase->C->top();      // Dead path?  Use a dead data op
     } else {
       x = this->clone();        // Else clone up the data op
       the_clone = x;            // Remember for possible deletion.
       // Alter data node to use pre-phi inputs
-      if( this->in(0) == region ) {
-        x->set_req( 0, region->in(i) );
+      if (this->in(0) == region) {
+        x->set_req(0, region->in(i));
       } else {
-        x->set_req( 0, NULL );
+        x->set_req(0, NULL);
       }
-      for( uint j = 1; j < this->req(); j++ ) {
+      for (uint j = 1; j < this->req(); j++) {
         Node *in = this->in(j);
-        if( in->is_Phi() && in->in(0) == region )
-          x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone
+        if (in->is_Phi() && in->in(0) == region)
+          x->set_req(j, in->in(i)); // Use pre-Phi input for the clone
       }
     }
     // Check for a 'win' on some paths
@@ -1321,12 +1323,11 @@ Node *LoadNode::split_through_phi(PhaseGVN *phase) {
     bool singleton = t->singleton();
 
     // See comments in PhaseIdealLoop::split_thru_phi().
-    if( singleton && t == Type::TOP ) {
+    if (singleton && t == Type::TOP) {
       singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
     }
 
-    if( singleton ) {
-      wins++;
+    if (singleton) {
       x = igvn->makecon(t);
     } else {
       // We now call Identity to try to simplify the cloned node.
@@ -1340,13 +1341,11 @@ Node *LoadNode::split_through_phi(PhaseGVN *phase) {
       // igvn->type(x) is set to x->Value() already.
       x->raise_bottom_type(t);
       Node *y = x->Identity(igvn);
-      if( y != x ) {
-        wins++;
+      if (y != x) {
         x = y;
       } else {
         y = igvn->hash_find(x);
-        if( y ) {
-          wins++;
+        if (y) {
           x = y;
         } else {
           // Else x is a new node we are keeping
@@ -1360,13 +1359,9 @@ Node *LoadNode::split_through_phi(PhaseGVN *phase) {
       igvn->remove_dead_node(the_clone);
     phi->set_req(i, x);
   }
-  if( wins > 0 ) {
-    // Record Phi
-    igvn->register_new_node_with_optimizer(phi);
-    return phi;
-  }
-  igvn->remove_dead_node(phi);
-  return NULL;
+  // Record Phi
+  igvn->register_new_node_with_optimizer(phi);
+  return phi;
 }
 
 //------------------------------Ideal------------------------------------------
@@ -1677,14 +1672,15 @@ const Type *LoadNode::Value( PhaseTransform *phase ) const {
   // If we are loading from a freshly-allocated object, produce a zero,
   // if the load is provably beyond the header of the object.
   // (Also allow a variable load from a fresh array to produce zero.)
-  if (ReduceFieldZeroing) {
+  const TypeOopPtr *tinst = tp->isa_oopptr();
+  bool is_instance = (tinst != NULL) && tinst->is_known_instance_field();
+  if (ReduceFieldZeroing || is_instance) {
     Node* value = can_see_stored_value(mem,phase);
     if (value != NULL && value->is_Con())
       return value->bottom_type();
   }
 
-  const TypeOopPtr *tinst = tp->isa_oopptr();
-  if (tinst != NULL && tinst->is_known_instance_field()) {
+  if (is_instance) {
     // If we have an instance type and our memory input is the
     // programs's initial memory state, there is no matching store,
     // so just return a zero of the appropriate type