Control unit
Control units use many methods to keep a pipeline full and avoid stalls. For example, even simple control units can assume that a backwards branch, to a lower-numbered, earlier instruction, is a loop, and will be repeated. So, a control unit with this design will always fill the pipeline with the backwards branch path. If a compiler can detect the most frequently-taken direction of a branch, the compiler can just produce instructions so that the most frequently taken branch is the preferred direction of branch. In a like way, a control unit might get hints from the compiler: Some computers have instructions that can encode hints from the compiler about the direction of branch.