[perl #131297] [PERF][REGEX] `|@a` is apparently-equivalent to just `@a` but is 70x slower

[Aleks-Daniel Jakimenko-Aleksejev via RT]

Closing, explanation here: https://github.com/rakudo/rakudo/issues/2708

On 2017-05-12 07:52:34, c...@zoffix.com wrote:
> https://irclog.perlgeek.de/perl6-dev/2017-05-12#i_14572067
>
> 14:49 m: my @a = 1..12; for ('a' x 100 ~ " -- Jan-12-2017")
> xx 100 { when /'-- ' |@a '-' \d**2 '-' \d**4 / { } }; say now - INIT
> now
> 14:49 camelia rakudo-moar 94c4e7: OUTPUT: «4.269762␤»
> 14:49 Zoffix m: my @a = 1..12; for ('a' x 100 ~ " -- Jan-12-2017")
> xx 100 { when /'-- ' ||@a '-' \d**2 '-' \d**4 / { } }; say now - INIT
> now
> 14:49 camelia rakudo-moar 94c4e7: OUTPUT: «0.3336069␤»
> 14:49 Zoffix m: my @a = 1..12; for ('a' x 100 ~ " -- Jan-12-2017")
> xx 100 { when /'-- ' @a '-' \d**2 '-' \d**4 / { } }; say now - INIT
> now
> 14:49 camelia rakudo-moar 94c4e7: OUTPUT: «0.0607072␤»
> 14:49 Zoffix m: say 4.269762/0.0607072
> 14:49 camelia rakudo-moar 94c4e7: OUTPUT: «70.3337001␤»
> 14:49 Zoffix apparently-equivalent but 70x slower
> 14:50 timotimo well well, we still have a lot of
> opportunities to improve these things