in reply to Re^9: Regex match at the beginning or end of string
in thread Regex match at the beginning or end of string

If we're allowed to cheat then the difference moves into the realms of run to run variability
Rate b a d c b 82.7/s -- -97% -97% -99% a 2657/s 3112% -- -3% -56% d 2748/s 3222% 3% -- -54% c 5982/s 7132% 125% 118% -- 388200:12000:829800:389700
I'm not sure what cheating is in this context, but that's not the point. The only "run to run" variability I see is between cases a and d, which are almost identical. Case c is more than twice as fast of any of the other variants.