changeset 59254:fc072587a25c

8244813: [BACKOUT] 8244523: Shenandoah: Remove null-handling in LRB expansion Reviewed-by: shade
author rkennke
date Tue, 12 May 2020 16:12:37 +0200
parents e62705474229
children a5844fa67a60
files src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.hpp src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.hpp
diffstat 4 files changed, 316 insertions(+), 23 deletions(-) [+]
line wrap: on
line diff
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp	Tue May 12 10:01:36 2020 -0400
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp	Tue May 12 16:12:37 2020 +0200
@@ -481,16 +481,16 @@
   return TypeFunc::make(domain, range);
 }
 
-const TypeFunc* ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type(const Type* value_type) {
+const TypeFunc* ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type() {
   const Type **fields = TypeTuple::fields(2);
-  fields[TypeFunc::Parms+0] = value_type;           // original field value
+  fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
   fields[TypeFunc::Parms+1] = TypeRawPtr::BOTTOM;   // original load address
 
   const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
 
   // create result type (range)
   fields = TypeTuple::fields(1);
-  fields[TypeFunc::Parms+0] = value_type;
+  fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL;
   const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+1, fields);
 
   return TypeFunc::make(domain, range);
@@ -1059,10 +1059,37 @@
       }
     }
   }
-  if (can_reshape &&
-      n->Opcode() == Op_If &&
-      ShenandoahBarrierC2Support::is_heap_stable_test(n) &&
-      n->in(0) != NULL) {
+  if (n->Opcode() == Op_CmpP) {
+    Node* in1 = n->in(1);
+    Node* in2 = n->in(2);
+    if (in1->bottom_type() == TypePtr::NULL_PTR) {
+      in2 = step_over_gc_barrier(in2);
+    }
+    if (in2->bottom_type() == TypePtr::NULL_PTR) {
+      in1 = step_over_gc_barrier(in1);
+    }
+    PhaseIterGVN* igvn = phase->is_IterGVN();
+    if (in1 != n->in(1)) {
+      if (igvn != NULL) {
+        n->set_req_X(1, in1, igvn);
+      } else {
+        n->set_req(1, in1);
+      }
+      assert(in2 == n->in(2), "only one change");
+      return n;
+    }
+    if (in2 != n->in(2)) {
+      if (igvn != NULL) {
+        n->set_req_X(2, in2, igvn);
+      } else {
+        n->set_req(2, in2);
+      }
+      return n;
+    }
+  } else if (can_reshape &&
+             n->Opcode() == Op_If &&
+             ShenandoahBarrierC2Support::is_heap_stable_test(n) &&
+             n->in(0) != NULL) {
     Node* dom = n->in(0);
     Node* prev_dom = n;
     int op = n->Opcode();
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.hpp	Tue May 12 10:01:36 2020 -0400
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.hpp	Tue May 12 16:12:37 2020 +0200
@@ -103,7 +103,7 @@
 
   static const TypeFunc* write_ref_field_pre_entry_Type();
   static const TypeFunc* shenandoah_clone_barrier_Type();
-  static const TypeFunc* shenandoah_load_reference_barrier_Type(const Type* value_type);
+  static const TypeFunc* shenandoah_load_reference_barrier_Type();
   virtual bool has_load_barrier_nodes() const { return true; }
 
   // This is the entry-point for the backend to perform accesses through the Access API.
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp	Tue May 12 10:01:36 2020 -0400
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp	Tue May 12 16:12:37 2020 +0200
@@ -919,6 +919,76 @@
   }
 }
 
+Node* ShenandoahBarrierC2Support::clone_null_check(Node*& c, Node* val, Node* unc_ctrl, PhaseIdealLoop* phase) {
+  IdealLoopTree *loop = phase->get_loop(c);
+  Node* iff = unc_ctrl->in(0);
+  assert(iff->is_If(), "broken");
+  Node* new_iff = iff->clone();
+  new_iff->set_req(0, c);
+  phase->register_control(new_iff, loop, c);
+  Node* iffalse = new IfFalseNode(new_iff->as_If());
+  phase->register_control(iffalse, loop, new_iff);
+  Node* iftrue = new IfTrueNode(new_iff->as_If());
+  phase->register_control(iftrue, loop, new_iff);
+  c = iftrue;
+  const Type *t = phase->igvn().type(val);
+  assert(val->Opcode() == Op_CastPP, "expect cast to non null here");
+  Node* uncasted_val = val->in(1);
+  val = new CastPPNode(uncasted_val, t);
+  val->init_req(0, c);
+  phase->register_new_node(val, c);
+  return val;
+}
+
+void ShenandoahBarrierC2Support::fix_null_check(Node* unc, Node* unc_ctrl, Node* new_unc_ctrl,
+                                                Unique_Node_List& uses, PhaseIdealLoop* phase) {
+  IfNode* iff = unc_ctrl->in(0)->as_If();
+  Node* proj = iff->proj_out(0);
+  assert(proj != unc_ctrl, "bad projection");
+  Node* use = proj->unique_ctrl_out();
+
+  assert(use == unc || use->is_Region(), "what else?");
+
+  uses.clear();
+  if (use == unc) {
+    phase->set_idom(use, new_unc_ctrl, phase->dom_depth(use));
+    for (uint i = 1; i < unc->req(); i++) {
+      Node* n = unc->in(i);
+      if (phase->has_ctrl(n) && phase->get_ctrl(n) == proj) {
+        uses.push(n);
+      }
+    }
+  } else {
+    assert(use->is_Region(), "what else?");
+    uint idx = 1;
+    for (; use->in(idx) != proj; idx++);
+    for (DUIterator_Fast imax, i = use->fast_outs(imax); i < imax; i++) {
+      Node* u = use->fast_out(i);
+      if (u->is_Phi() && phase->get_ctrl(u->in(idx)) == proj) {
+        uses.push(u->in(idx));
+      }
+    }
+  }
+  for(uint next = 0; next < uses.size(); next++ ) {
+    Node *n = uses.at(next);
+    assert(phase->get_ctrl(n) == proj, "bad control");
+    phase->set_ctrl_and_loop(n, new_unc_ctrl);
+    if (n->in(0) == proj) {
+      phase->igvn().replace_input_of(n, 0, new_unc_ctrl);
+    }
+    for (uint i = 0; i < n->req(); i++) {
+      Node* m = n->in(i);
+      if (m != NULL && phase->has_ctrl(m) && phase->get_ctrl(m) == proj) {
+        uses.push(m);
+      }
+    }
+  }
+
+  phase->igvn().rehash_node_delayed(use);
+  int nb = use->replace_edge(proj, new_unc_ctrl);
+  assert(nb == 1, "only use expected");
+}
+
 void ShenandoahBarrierC2Support::test_in_cset(Node*& ctrl, Node*& not_cset_ctrl, Node* val, Node* raw_mem, PhaseIdealLoop* phase) {
   Node* old_ctrl = ctrl;
   PhaseIterGVN& igvn = phase->igvn();
@@ -970,7 +1040,7 @@
   address calladdr = is_native ? CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_native)
                                : target;
   const char* name = is_native ? "load_reference_barrier_native" : "load_reference_barrier";
-  Node* call = new CallLeafNode(ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type(obj_type), calladdr, name, TypeRawPtr::BOTTOM);
+  Node* call = new CallLeafNode(ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type(), calladdr, name, TypeRawPtr::BOTTOM);
 
   call->init_req(TypeFunc::Control, ctrl);
   call->init_req(TypeFunc::I_O, phase->C->top());
@@ -986,6 +1056,8 @@
   phase->register_new_node(result_mem, call);
   val = new ProjNode(call, TypeFunc::Parms);
   phase->register_new_node(val, call);
+  val = new CheckCastPPNode(ctrl, val, obj_type);
+  phase->register_new_node(val, ctrl);
 }
 
 void ShenandoahBarrierC2Support::fix_ctrl(Node* barrier, Node* region, const MemoryGraphFixer& fixer, Unique_Node_List& uses, Unique_Node_List& uses_to_ignore, uint last, PhaseIdealLoop* phase) {
@@ -1091,6 +1163,119 @@
     }
 
     Node* ctrl = phase->get_ctrl(lrb);
+    Node* val = lrb->in(ShenandoahLoadReferenceBarrierNode::ValueIn);
+
+    CallStaticJavaNode* unc = NULL;
+    Node* unc_ctrl = NULL;
+    Node* uncasted_val = val;
+
+    for (DUIterator_Fast imax, i = lrb->fast_outs(imax); i < imax; i++) {
+      Node* u = lrb->fast_out(i);
+      if (u->Opcode() == Op_CastPP &&
+          u->in(0) != NULL &&
+          phase->is_dominator(u->in(0), ctrl)) {
+        const Type* u_t = phase->igvn().type(u);
+
+        if (u_t->meet(TypePtr::NULL_PTR) != u_t &&
+            u->in(0)->Opcode() == Op_IfTrue &&
+            u->in(0)->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none) &&
+            u->in(0)->in(0)->is_If() &&
+            u->in(0)->in(0)->in(1)->Opcode() == Op_Bool &&
+            u->in(0)->in(0)->in(1)->as_Bool()->_test._test == BoolTest::ne &&
+            u->in(0)->in(0)->in(1)->in(1)->Opcode() == Op_CmpP &&
+            u->in(0)->in(0)->in(1)->in(1)->in(1) == val &&
+            u->in(0)->in(0)->in(1)->in(1)->in(2)->bottom_type() == TypePtr::NULL_PTR) {
+          IdealLoopTree* loop = phase->get_loop(ctrl);
+          IdealLoopTree* unc_loop = phase->get_loop(u->in(0));
+
+          if (!unc_loop->is_member(loop)) {
+            continue;
+          }
+
+          Node* branch = no_branches(ctrl, u->in(0), false, phase);
+          assert(branch == NULL || branch == NodeSentinel, "was not looking for a branch");
+          if (branch == NodeSentinel) {
+            continue;
+          }
+
+          phase->igvn().replace_input_of(u, 1, val);
+          phase->igvn().replace_input_of(lrb, ShenandoahLoadReferenceBarrierNode::ValueIn, u);
+          phase->set_ctrl(u, u->in(0));
+          phase->set_ctrl(lrb, u->in(0));
+          unc = u->in(0)->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none);
+          unc_ctrl = u->in(0);
+          val = u;
+
+          for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) {
+            Node* u = val->fast_out(j);
+            if (u == lrb) continue;
+            phase->igvn().rehash_node_delayed(u);
+            int nb = u->replace_edge(val, lrb);
+            --j; jmax -= nb;
+          }
+
+          RegionNode* r = new RegionNode(3);
+          IfNode* iff = unc_ctrl->in(0)->as_If();
+
+          Node* ctrl_use = unc_ctrl->unique_ctrl_out();
+          Node* unc_ctrl_clone = unc_ctrl->clone();
+          phase->register_control(unc_ctrl_clone, loop, iff);
+          Node* c = unc_ctrl_clone;
+          Node* new_cast = clone_null_check(c, val, unc_ctrl_clone, phase);
+          r->init_req(1, new_cast->in(0)->in(0)->as_If()->proj_out(0));
+
+          phase->igvn().replace_input_of(unc_ctrl, 0, c->in(0));
+          phase->set_idom(unc_ctrl, c->in(0), phase->dom_depth(unc_ctrl));
+          phase->lazy_replace(c, unc_ctrl);
+          c = NULL;;
+          phase->igvn().replace_input_of(val, 0, unc_ctrl_clone);
+          phase->set_ctrl(val, unc_ctrl_clone);
+
+          IfNode* new_iff = new_cast->in(0)->in(0)->as_If();
+          fix_null_check(unc, unc_ctrl_clone, r, uses, phase);
+          Node* iff_proj = iff->proj_out(0);
+          r->init_req(2, iff_proj);
+          phase->register_control(r, phase->ltree_root(), iff);
+
+          Node* new_bol = new_iff->in(1)->clone();
+          Node* new_cmp = new_bol->in(1)->clone();
+          assert(new_cmp->Opcode() == Op_CmpP, "broken");
+          assert(new_cmp->in(1) == val->in(1), "broken");
+          new_bol->set_req(1, new_cmp);
+          new_cmp->set_req(1, lrb);
+          phase->register_new_node(new_bol, new_iff->in(0));
+          phase->register_new_node(new_cmp, new_iff->in(0));
+          phase->igvn().replace_input_of(new_iff, 1, new_bol);
+          phase->igvn().replace_input_of(new_cast, 1, lrb);
+
+          for (DUIterator_Fast imax, i = lrb->fast_outs(imax); i < imax; i++) {
+            Node* u = lrb->fast_out(i);
+            if (u == new_cast || u == new_cmp) {
+              continue;
+            }
+            phase->igvn().rehash_node_delayed(u);
+            int nb = u->replace_edge(lrb, new_cast);
+            assert(nb > 0, "no update?");
+            --i; imax -= nb;
+          }
+
+          for (DUIterator_Fast imax, i = val->fast_outs(imax); i < imax; i++) {
+            Node* u = val->fast_out(i);
+            if (u == lrb) {
+              continue;
+            }
+            phase->igvn().rehash_node_delayed(u);
+            int nb = u->replace_edge(val, new_cast);
+            assert(nb > 0, "no update?");
+            --i; imax -= nb;
+          }
+
+          ctrl = unc_ctrl_clone;
+          phase->set_ctrl_and_loop(lrb, ctrl);
+          break;
+        }
+      }
+    }
     if ((ctrl->is_Proj() && ctrl->in(0)->is_CallJava()) || ctrl->is_CallJava()) {
       CallNode* call = ctrl->is_Proj() ? ctrl->in(0)->as_CallJava() : ctrl->as_CallJava();
       if (call->entry_point() == OptoRuntime::rethrow_stub()) {
@@ -1231,45 +1416,90 @@
     Node* ctrl = phase->get_ctrl(lrb);
     Node* val = lrb->in(ShenandoahLoadReferenceBarrierNode::ValueIn);
 
+
     Node* orig_ctrl = ctrl;
 
     Node* raw_mem = fixer.find_mem(ctrl, lrb);
     Node* init_raw_mem = raw_mem;
     Node* raw_mem_for_ctrl = fixer.find_mem(ctrl, NULL);
 
-    IdealLoopTree* loop = phase->get_loop(ctrl);
+    IdealLoopTree *loop = phase->get_loop(ctrl);
+    CallStaticJavaNode* unc = lrb->pin_and_expand_null_check(phase->igvn());
+    Node* unc_ctrl = NULL;
+    if (unc != NULL) {
+      if (val->in(ShenandoahLoadReferenceBarrierNode::Control) != ctrl) {
+        unc = NULL;
+      } else {
+        unc_ctrl = val->in(ShenandoahLoadReferenceBarrierNode::Control);
+      }
+    }
+
+    Node* uncasted_val = val;
+    if (unc != NULL) {
+      uncasted_val = val->in(1);
+    }
+
+    Node* heap_stable_ctrl = NULL;
+    Node* null_ctrl = NULL;
 
     assert(val->bottom_type()->make_oopptr(), "need oop");
     assert(val->bottom_type()->make_oopptr()->const_oop() == NULL, "expect non-constant");
 
-    enum { _heap_stable = 1, _not_cset, _evac_path, PATH_LIMIT };
+    enum { _heap_stable = 1, _not_cset, _evac_path, _null_path, PATH_LIMIT };
     Node* region = new RegionNode(PATH_LIMIT);
-    Node* val_phi = new PhiNode(region, val->bottom_type()->is_oopptr());
+    Node* val_phi = new PhiNode(region, uncasted_val->bottom_type()->is_oopptr());
     Node* raw_mem_phi = PhiNode::make(region, raw_mem, Type::MEMORY, TypeRawPtr::BOTTOM);
 
     // Stable path.
-    Node* heap_stable_ctrl = NULL;
     test_gc_state(ctrl, raw_mem, heap_stable_ctrl, phase, ShenandoahHeap::HAS_FORWARDED);
     IfNode* heap_stable_iff = heap_stable_ctrl->in(0)->as_If();
 
     // Heap stable case
     region->init_req(_heap_stable, heap_stable_ctrl);
-    val_phi->init_req(_heap_stable, val);
+    val_phi->init_req(_heap_stable, uncasted_val);
     raw_mem_phi->init_req(_heap_stable, raw_mem);
 
+    Node* reg2_ctrl = NULL;
+    // Null case
+    test_null(ctrl, val, null_ctrl, phase);
+    if (null_ctrl != NULL) {
+      reg2_ctrl = null_ctrl->in(0);
+      region->init_req(_null_path, null_ctrl);
+      val_phi->init_req(_null_path, uncasted_val);
+      raw_mem_phi->init_req(_null_path, raw_mem);
+    } else {
+      region->del_req(_null_path);
+      val_phi->del_req(_null_path);
+      raw_mem_phi->del_req(_null_path);
+    }
+
     // Test for in-cset.
     // Wires !in_cset(obj) to slot 2 of region and phis
     Node* not_cset_ctrl = NULL;
-    test_in_cset(ctrl, not_cset_ctrl, val, raw_mem, phase);
+    test_in_cset(ctrl, not_cset_ctrl, uncasted_val, raw_mem, phase);
     if (not_cset_ctrl != NULL) {
+      if (reg2_ctrl == NULL) reg2_ctrl = not_cset_ctrl->in(0);
       region->init_req(_not_cset, not_cset_ctrl);
-      val_phi->init_req(_not_cset, val);
+      val_phi->init_req(_not_cset, uncasted_val);
       raw_mem_phi->init_req(_not_cset, raw_mem);
     }
 
+    // Resolve object when orig-value is in cset.
+    // Make the unconditional resolve for fwdptr.
+    Node* new_val = uncasted_val;
+    if (unc_ctrl != NULL) {
+      // Clone the null check in this branch to allow implicit null check
+      new_val = clone_null_check(ctrl, val, unc_ctrl, phase);
+      fix_null_check(unc, unc_ctrl, ctrl->in(0)->as_If()->proj_out(0), uses, phase);
+
+      IfNode* iff = unc_ctrl->in(0)->as_If();
+      phase->igvn().replace_input_of(iff, 1, phase->igvn().intcon(1));
+    }
+
     // Call lrb-stub and wire up that path in slots 4
     Node* result_mem = NULL;
 
+    Node* fwd = new_val;
     Node* addr;
     if (ShenandoahSelfFixing) {
       VectorSet visited(Thread::current()->resource_area());
@@ -1302,9 +1532,9 @@
         }
       }
     }
-    call_lrb_stub(ctrl, val, addr, result_mem, raw_mem, lrb->is_native(), phase);
+    call_lrb_stub(ctrl, fwd, addr, result_mem, raw_mem, lrb->is_native(), phase);
     region->init_req(_evac_path, ctrl);
-    val_phi->init_req(_evac_path, val);
+    val_phi->init_req(_evac_path, fwd);
     raw_mem_phi->init_req(_evac_path, result_mem);
 
     phase->register_control(region, loop, heap_stable_iff);
@@ -1316,6 +1546,20 @@
 
     ctrl = orig_ctrl;
 
+    if (unc != NULL) {
+      for (DUIterator_Fast imax, i = val->fast_outs(imax); i < imax; i++) {
+        Node* u = val->fast_out(i);
+        Node* c = phase->ctrl_or_self(u);
+        if (u != lrb && (c != ctrl || is_dominator_same_ctrl(c, lrb, u, phase))) {
+          phase->igvn().rehash_node_delayed(u);
+          int nb = u->replace_edge(val, out_val);
+          --i, imax -= nb;
+        }
+      }
+      if (val->outcnt() == 0) {
+        phase->igvn()._worklist.push(val);
+      }
+    }
     phase->igvn().replace_node(lrb, out_val);
 
     follow_barrier_uses(out_val, ctrl, uses, phase);
@@ -2943,11 +3187,6 @@
     bool visit_users = false;
     switch (n->Opcode()) {
       case Op_CallStaticJava:
-        // Uncommon traps don't need barriers, values are handled during deoptimization. It also affects
-        // optimizing null-checks into implicit null-checks.
-        if (n->as_CallStaticJava()->uncommon_trap_request() != 0) {
-          break;
-        }
       case Op_CallDynamicJava:
       case Op_CallLeaf:
       case Op_CallLeafNoFP:
@@ -3089,3 +3328,26 @@
   // No need for barrier found.
   return true;
 }
+
+CallStaticJavaNode* ShenandoahLoadReferenceBarrierNode::pin_and_expand_null_check(PhaseIterGVN& igvn) {
+  Node* val = in(ValueIn);
+
+  const Type* val_t = igvn.type(val);
+
+  if (val_t->meet(TypePtr::NULL_PTR) != val_t &&
+      val->Opcode() == Op_CastPP &&
+      val->in(0) != NULL &&
+      val->in(0)->Opcode() == Op_IfTrue &&
+      val->in(0)->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none) &&
+      val->in(0)->in(0)->is_If() &&
+      val->in(0)->in(0)->in(1)->Opcode() == Op_Bool &&
+      val->in(0)->in(0)->in(1)->as_Bool()->_test._test == BoolTest::ne &&
+      val->in(0)->in(0)->in(1)->in(1)->Opcode() == Op_CmpP &&
+      val->in(0)->in(0)->in(1)->in(1)->in(1) == val->in(1) &&
+      val->in(0)->in(0)->in(1)->in(1)->in(2)->bottom_type() == TypePtr::NULL_PTR) {
+    assert(val->in(0)->in(0)->in(1)->in(1)->in(1) == val->in(1), "");
+    CallStaticJavaNode* unc = val->in(0)->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none);
+    return unc;
+  }
+  return NULL;
+}
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.hpp	Tue May 12 10:01:36 2020 -0400
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.hpp	Tue May 12 16:12:37 2020 +0200
@@ -63,6 +63,9 @@
   static void call_lrb_stub(Node*& ctrl, Node*& val, Node* load_addr, Node*& result_mem, Node* raw_mem, bool is_native, PhaseIdealLoop* phase);
   static void test_in_cset(Node*& ctrl, Node*& not_cset_ctrl, Node* val, Node* raw_mem, PhaseIdealLoop* phase);
   static void move_gc_state_test_out_of_loop(IfNode* iff, PhaseIdealLoop* phase);
+  static Node* clone_null_check(Node*& c, Node* val, Node* unc_ctrl, PhaseIdealLoop* phase);
+  static void fix_null_check(Node* unc, Node* unc_ctrl, Node* new_unc_ctrl, Unique_Node_List& uses,
+                             PhaseIdealLoop* phase);
   static void merge_back_to_back_tests(Node* n, PhaseIdealLoop* phase);
   static bool identical_backtoback_ifs(Node *n, PhaseIdealLoop* phase);
   static void fix_ctrl(Node* barrier, Node* region, const MemoryGraphFixer& fixer, Unique_Node_List& uses, Unique_Node_List& uses_to_ignore, uint last, PhaseIdealLoop* phase);
@@ -251,6 +254,7 @@
   virtual bool cmp( const Node &n ) const;
 
   bool is_redundant();
+  CallStaticJavaNode* pin_and_expand_null_check(PhaseIterGVN& igvn);
 
 private:
   bool needs_barrier(PhaseGVN* phase, Node* n);