# HG changeset patch
# Parent 7a64f4b361ce89962a19e207e1aed8b507b506ea
diff -r 7a64f4b361ce -r 637dd853c3f3 src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp	Thu Jun 27 14:22:15 2019 +0200
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp	Tue Jul 02 19:57:08 2019 +0200
@@ -546,7 +546,7 @@
 
   if (access.is_oop()) {
     if (ShenandoahLoadRefBarrier) {
-      load = new ShenandoahLoadReferenceBarrierNode(NULL, load, adr);
+      load = new ShenandoahLoadReferenceBarrierNode(NULL, load);
       if (access.is_parse_access()) {
         load = static_cast<C2ParseAccess &>(access).kit()->gvn().transform(load);
       } else {
@@ -631,7 +631,7 @@
       load_store = kit->gvn().transform(new DecodeNNode(load_store, load_store->get_ptr_type()));
     }
 #endif
-    load_store = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, load_store, kit->null()));
+    load_store = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, load_store));
     return load_store;
   }
   return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
@@ -699,7 +699,7 @@
   }
   Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, val, value_type);
   if (access.is_oop()) {
-    result = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, result, kit->null()));
+    result = kit->gvn().transform(new ShenandoahLoadReferenceBarrierNode(NULL, result));
     shenandoah_write_barrier_pre(kit, false /* do_load */,
                                  NULL, NULL, max_juint, NULL, NULL,
                                  result /* pre_val */, T_OBJECT);
diff -r 7a64f4b361ce -r 637dd853c3f3 src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp	Thu Jun 27 14:22:15 2019 +0200
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp	Tue Jul 02 19:57:08 2019 +0200
@@ -1523,7 +1523,9 @@
     // Call lrb-stub and wire up that path in slots 4
     Node* result_mem = NULL;
     Node* fwd = new_val;
-    call_lrb_stub(ctrl, fwd, lrb->in(ShenandoahLoadReferenceBarrierNode::LoadAddr), result_mem, raw_mem, phase);
+    VectorSet visited(Thread::current()->resource_area());
+    Node* addr = get_load_addr(phase, visited, lrb);
+    call_lrb_stub(ctrl, fwd, addr, result_mem, raw_mem, phase);
     region->init_req(_evac_path, ctrl);
     val_phi->init_req(_evac_path, fwd);
     raw_mem_phi->init_req(_evac_path, result_mem);
@@ -1726,6 +1728,58 @@
 
 }
 
+Node* ShenandoahBarrierC2Support::get_load_addr(PhaseIdealLoop* phase, VectorSet& visited, Node* in) {
+  if (visited.test_set(in->_idx)) {
+    return NULL;
+  }
+  switch (in->Opcode()) {
+    case Op_Proj:
+      return get_load_addr(phase, visited, in->in(0));
+    case Op_CastPP:
+    case Op_CheckCastPP:
+    case Op_DecodeN:
+    case Op_EncodeP:
+      return get_load_addr(phase, visited, in->in(1));
+    case Op_CompareAndExchangeN:
+    case Op_CompareAndExchangeP:
+    case Op_GetAndSetN:
+    case Op_GetAndSetP:
+    case Op_LoadN:
+    case Op_LoadP:
+    case Op_ShenandoahCompareAndExchangeP:
+    case Op_ShenandoahCompareAndExchangeN:
+      return in->in(MemNode::Address);
+    case Op_Phi: {
+      Node* addr = NULL;
+      for (uint i = 1; i < in->req(); i++) {
+        Node* addr1 = get_load_addr(phase, visited, in->in(i));
+        if (addr == NULL) {
+          addr = addr1;
+        }
+        if (addr != addr1) {
+          return phase->igvn().zerocon(T_OBJECT);
+        }
+      }
+      return addr;
+    }
+    case Op_ShenandoahLoadReferenceBarrier:
+      return get_load_addr(phase, visited, in->in(ShenandoahLoadReferenceBarrierNode::ValueIn));
+    case Op_CallDynamicJava:
+    case Op_CallLeaf:
+    case Op_CallStaticJava:
+    case Op_ConN:
+    case Op_ConP:
+      return phase->igvn().zerocon(T_OBJECT);
+    default:
+#ifdef ASSERT
+      in->dump();
+      ShouldNotReachHere();
+#endif
+      return phase->igvn().zerocon(T_OBJECT);
+  }
+
+}
+
 void ShenandoahBarrierC2Support::move_heap_stable_test_out_of_loop(IfNode* iff, PhaseIdealLoop* phase) {
   IdealLoopTree *loop = phase->get_loop(iff);
   Node* loop_head = loop->_head;
@@ -2966,8 +3020,8 @@
   }
 }
 
-ShenandoahLoadReferenceBarrierNode::ShenandoahLoadReferenceBarrierNode(Node* ctrl, Node* obj, Node* load_addr)
-: Node(ctrl, obj, load_addr) {
+ShenandoahLoadReferenceBarrierNode::ShenandoahLoadReferenceBarrierNode(Node* ctrl, Node* obj)
+: Node(ctrl, obj) {
   ShenandoahBarrierSetC2::bsc2()->state()->add_load_reference_barrier(this);
 }
 
diff -r 7a64f4b361ce -r 637dd853c3f3 src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.hpp
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.hpp	Thu Jun 27 14:22:15 2019 +0200
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.hpp	Tue Jul 02 19:57:08 2019 +0200
@@ -71,6 +71,7 @@
   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);
   static IfNode* find_unswitching_candidate(const IdealLoopTree *loop, PhaseIdealLoop* phase);
 
+  static Node* get_load_addr(PhaseIdealLoop* phase, VectorSet& visited, Node* lrb);
 public:
   static bool is_dominator(Node* d_c, Node* n_c, Node* d, Node* n, PhaseIdealLoop* phase);
   static bool is_dominator_same_ctrl(Node* c, Node* d, Node* n, PhaseIdealLoop* phase);
@@ -227,15 +228,14 @@
 public:
   enum {
     Control,
-    ValueIn,
-    LoadAddr
+    ValueIn
   };
 
   enum Strength {
     NONE, WEAK, STRONG, NA
   };
 
-  ShenandoahLoadReferenceBarrierNode(Node* ctrl, Node* val, Node* load_addr);
+  ShenandoahLoadReferenceBarrierNode(Node* ctrl, Node* val);
 
   virtual int Opcode() const;
   virtual const Type* bottom_type() const;