It makes no sense to initialize such event with nullptr. Favor the reference version for safer behavior. Change-Id: I695f41362a56aca98ceb52d49cf84be43f1465a2 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67656 Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br> Tested-by: kokoro <noreply+kokoro@google.com> Maintainer: Daniel Carvalho <odanrc@yahoo.com.br>