Let us suppose this processor supports not only add, sub, and, or$,$ lw$,$ sw$,$ beq, but also slt$,$ j$.$

Let us suppose the MemToReg control line is defective and gets stuck at $0.$ Which of the supported instructions will always execute correctly? And which ones can possibly execute correctly, and under what circumstances?

$($By $$execute correctly$$ we mean $$produce the correct results, AND do not produce unintended side effects$.$ The processor without a defective control line is the standard for determining correct results and side effects.$)$