• Suppose we have two predictors, A and B
• Suppose A works well for some applications (for
example those like go with dynamic but highly-
correlated branches)
• Suppose B works well for highly biased branches
• A is best for some programs, B is best for others
• Idea: build a “selective” predictor to choose, for each
branch, the predictor with the best track record to date
• With care, we can guarantee to do better than A or B
separately
• At considerable expense!
18