Hi Sheng,
Thanks for reaching out. From the qsys file, <module name="fifo_0" kind="fifo" version="16.1" enabled="1" autoexport="1">, <parameter name="hdlLanguage" value="VERILOG">. It wraps around dcfifo, which instantiate dcfifo_mixed_width. I notice the fifo version is 16.1 and the Quartus Prime version is 18.1.0
From the Help menu of the GUI : Quartus Prime Version 18.1.0 Build 625 09/12/2018 SJ Standard Edition
We use qsys-generate to regenerate the core files from qsys files, which are checked in to git repo, then use msim_setup.tcl to generate simulation libraries for the cores.
Thanks,
-Minh