And, some actual timings (code: https://godbolt.org/z/qnWEqs446 https://godbolt.org/z/qnWEqs446): $ clang -DLEN=1024 -DITERATIONS=100000 -O3 switch.c && ./

And, some actual timings (code: https://godbolt.org/z/qnWEqs446 https://godbolt.org/z/qnWEqs446): $ clang -DLEN=1024 -DITERATIONS=100000 -O3 switch.c && ./a.out predictable: call_table: 173.1ms switch_cases: 59.6ms random: call_table: 536.2ms switch_cases: 450.4ms $ gcc -DLEN=1024 -DITERATIONS=100000 -O3 -fcf-protection=none switch.c && ./a.out predictable: call_table: 174.5ms switch_cases: 114.7ms random: call_table: 581.8ms switch_cases: 108.8ms $ clang -DLEN=64 -DITERATIONS=2000000 -O3 switch.c && ./a.out predictable: call_table: 230.6ms switch_cases: 116.0ms random: call_table: 218.7ms switch_cases: 158.2ms $ gcc -DLEN=64 -DITERATIONS=2000000 -O3 -fcf-protection=none switch.c && ./a.out predictable: call_table: 872.7ms switch_cases: 146.3ms random: call_table: 740.4ms switch_cases: 132.2ms The switch is faster in all cases, often by a big margin.