Leveraging dynamic slicing to enhance indirect branch prediction

An indirect branch specifies where the address of the next instruction to execute is located. The address to be jumped to is not known until the instruction is executed. Indirect branches can incur a significant fraction of branch misprediction overhead even though they remain less frequent than the more predictable conditional branches. Indirect branch instructions implement multiway branch statements and virtual function calls in object-oriented languages. Multiple targets indirect branch instructions are difficult to predict. We employ dynamic slicing to categorize indirect branches and use the most convenient predictor for each category. We also propose Dynamic Slicing directed Indirect Branch (DSIB) predictor, a profiling based target address prediction technique for indirect branch instructions. We compare the proposed predictor to VBBI and ITTAGE predictors. DSIB enhances prediction accuracy by 13% and 9% over VBBI and ITTAGE respectively. DSIB also results in IPC improvement of 11%, 4.2% and 3.55% over BTB, VBBI and ITTAGE respectively.