src/hotspot/share/opto/c2compiler.cpp

*** 545,554 ****
--- 545,560 ----
    case vmIntrinsics::_getClassId:
    case vmIntrinsics::_getEventWriter:
  #endif
    case vmIntrinsics::_currentTimeMillis:
    case vmIntrinsics::_nanoTime:
+     break;
+   case vmIntrinsics::_writeback0:
+   case vmIntrinsics::_writebackPreSync0:
+   case vmIntrinsics::_writebackPostSync0:
+     if (getenv("DISABLE_UNSAFE_WRITEBACK_INTRINSIC")) return false;
+     break;
    case vmIntrinsics::_allocateInstance:
    case vmIntrinsics::_allocateUninitializedArray:
    case vmIntrinsics::_newArray:
    case vmIntrinsics::_getLength:
    case vmIntrinsics::_copyOf: