src/share/vm/opto/graphKit.cpp

*** 4196,4207 ****
                                       Node* adr,
                                       uint alias_idx,
                                       Node* val,
                                       BasicType bt,
                                       bool use_precise) {
!   // If we are writing a NULL then we need no post barrier
  
    if (val != NULL && val->is_Con() && val->bottom_type() == TypePtr::NULL_PTR) {
      // Must be NULL
      const Type* t = val->bottom_type();
      assert(t == Type::TOP || t == TypePtr::NULL_PTR, "must be NULL");
      // No post barrier if writing NULLx
--- 4196,4215 ----
                                       Node* adr,
                                       uint alias_idx,
                                       Node* val,
                                       BasicType bt,
                                       bool use_precise) {
!   if (val == NULL) {
!     // The Object.clone() intrinsic uses this path if !ReduceInitialCardMarks.
!     // We don't need a barrier here because the destination is a newly allocated object
!     // in Eden. Otherwise, GC verification breaks because we assume that cards in Eden
!     // are set to 'g1_young_gen' (see G1SATBCardTableModRefBS::verify_g1_young_region()).
!     assert(!use_ReduceInitialCardMarks(), "can only happen with card marking");
!     return;
!   }
  
+   // If we are writing a NULL then we need no post barrier
    if (val != NULL && val->is_Con() && val->bottom_type() == TypePtr::NULL_PTR) {
      // Must be NULL
      const Type* t = val->bottom_type();
      assert(t == Type::TOP || t == TypePtr::NULL_PTR, "must be NULL");
      // No post barrier if writing NULLx
*** 4272,4284 ****
    // Combine card table base and card offset
    Node* card_adr = __ AddP(no_base, byte_map_base_node(), card_offset );
  
    // If we know the value being stored does it cross regions?
  
-   if (val != NULL) {
-     // Does the store cause us to cross regions?
- 
      // Should be able to do an unsigned compare of region_size instead of
      // and extra shift. Do we have an unsigned compare??
      // Node* region_size = __ ConI(1 << HeapRegion::LogOfHRGrainBytes);
      Node* xor_res =  __ URShiftX ( __ XorX( cast,  __ CastPX(__ ctrl(), val)), __ ConI(HeapRegion::LogOfHRGrainBytes));
  
--- 4280,4289 ----
*** 4303,4316 ****
              g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
            } __ end_if();
          } __ end_if();
        } __ end_if();
      } __ end_if();
-   } else {
-     // Object.clone() instrinsic uses this path.
-     g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
-   }
  
    // Final sync IdealKit and GraphKit.
    final_sync(ideal);
  }
  #undef __
--- 4308,4317 ----