Synthesis tool optimizing out block?

Quartus removed duplicate registers/logic by default. You can globally turn it off under Assignments -> Setting -> Analysis and Synthesis -> More Settings -> Remove Duplicate Registers = Off. I don't recommend doing this globally, as most designs have some replication they don't know about and don't want. But you can also do it on a hierarchy or register level. For a hierarchy, right-click on it in the Hierarchy Browser and Locate -> Assignment Editor. Then in the Assignment find Remove Duplicate Registers and set it to Off. You can also just open the assignment editor and find registers directly in the To Column(Double Clock on an empty row in the To column, and an arrow will show up, taking you to the Node Finder). I do this when manually replicating logic to meet timing(I change it in the code and do it here.) You can also make these assignments directly in the code via comment/pragmas, but I prefer doing it in the .qsf since it is an Altera specific command.