8244595: [REDO] 8244523: Shenandoah: Remove null-handling in LRB expa…

…nsion

Reviewed-by: shade

src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp

@@ -481,16 +481,16 @@ const TypeFunc* ShenandoahBarrierSetC2::shenandoah_clone_barrier_Type() {
   return TypeFunc::make(domain, range);
 }
 
-const TypeFunc* ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type() {
+const TypeFunc* ShenandoahBarrierSetC2::shenandoah_load_reference_barrier_Type(const Type* value_type) {
   const Type **fields = TypeTuple::fields(2);
-  fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL; // original field value
+  fields[TypeFunc::Parms+0] = value_type;           // 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] = TypeInstPtr::NOTNULL;
+  fields[TypeFunc::Parms+0] = value_type;
   const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+1, fields);
 
   return TypeFunc::make(domain, range);
@@ -1059,37 +1059,10 @@ Node* ShenandoahBarrierSetC2::ideal_node(PhaseGVN* phase, Node* n, bool can_resh
       }
     }
   }
-  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) {
+  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();

src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.hpp

@@ -103,7 +103,7 @@ class ShenandoahBarrierSetC2 : public BarrierSetC2 {
 
   static const TypeFunc* write_ref_field_pre_entry_Type();
   static const TypeFunc* shenandoah_clone_barrier_Type();
-  static const TypeFunc* shenandoah_load_reference_barrier_Type();
+  static const TypeFunc* shenandoah_load_reference_barrier_Type(const Type* value_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.