src/hotspot/cpu/x86/c1_LIRAssembler_x86.cpp

*** 1676,1688 ****
      Label not_null;
      __ jccb(Assembler::notEqual, not_null);
      // Object is null; update MDO and exit
      Register mdo  = klass_RInfo;
      __ mov_metadata(mdo, md->constant_encoding());
!     Address data_addr(mdo, md->byte_offset_of_slot(data, DataLayout::header_offset()));
!     int header_bits = DataLayout::flag_mask_to_header_mask(BitData::null_seen_byte_constant());
!     __ orl(data_addr, header_bits);
      __ jmp(*obj_is_null);
      __ bind(not_null);
    } else {
      __ jcc(Assembler::equal, *obj_is_null);
    }
--- 1676,1688 ----
      Label not_null;
      __ jccb(Assembler::notEqual, not_null);
      // Object is null; update MDO and exit
      Register mdo  = klass_RInfo;
      __ mov_metadata(mdo, md->constant_encoding());
!     Address data_addr(mdo, md->byte_offset_of_slot(data, DataLayout::flags_offset()));
!     int header_bits = BitData::null_seen_byte_constant();
!     __ orb(data_addr, header_bits);
      __ jmp(*obj_is_null);
      __ bind(not_null);
    } else {
      __ jcc(Assembler::equal, *obj_is_null);
    }
*** 1822,1834 ****
        Label not_null;
        __ jccb(Assembler::notEqual, not_null);
        // Object is null; update MDO and exit
        Register mdo  = klass_RInfo;
        __ mov_metadata(mdo, md->constant_encoding());
!       Address data_addr(mdo, md->byte_offset_of_slot(data, DataLayout::header_offset()));
!       int header_bits = DataLayout::flag_mask_to_header_mask(BitData::null_seen_byte_constant());
!       __ orl(data_addr, header_bits);
        __ jmp(done);
        __ bind(not_null);
      } else {
        __ jcc(Assembler::equal, done);
      }
--- 1822,1834 ----
        Label not_null;
        __ jccb(Assembler::notEqual, not_null);
        // Object is null; update MDO and exit
        Register mdo  = klass_RInfo;
        __ mov_metadata(mdo, md->constant_encoding());
!       Address data_addr(mdo, md->byte_offset_of_slot(data, DataLayout::flags_offset()));
!       int header_bits = BitData::null_seen_byte_constant();
!       __ orb(data_addr, header_bits);
        __ jmp(done);
        __ bind(not_null);
      } else {
        __ jcc(Assembler::equal, done);
      }