Test for Ruby 4.0 performance regression

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README.md
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··· 1 + # Ruby 4.0 regexp test 2 + 3 + There seems to be some kind of performance regression in Ruby 4.0 which showed up in my project, which I think is centered around regexp matching. I extracted some minimal code from the project, which runs significantly slower on Ruby 4.0 than on 3.4. 4 + 5 + Running on my server, with 1000 loops: 6 + 7 + ``` 8 + $ asdf shell ruby 3.4.8 9 + $ ruby test.rb 1000 10 + 1000 * 940 = 940000 records in 7.439838799 -> 126346.82355299778 records/s 11 + $ asdf shell ruby 4.0.0 12 + $ ruby test.rb 1000 13 + 1000 * 940 = 940000 records in 13.67647823 -> 68731.14439198723 records/s 14 + ``` 15 + 16 + With YJIT: 17 + 18 + ``` 19 + $ asdf shell ruby 3.4.8 20 + $ RUBYOPT="--enable-yjit" ruby test.rb 1000 21 + 1000 * 940 = 940000 records in 7.20592409 -> 130448.22402507435 records/s 22 + $ asdf shell ruby 4.0.0 23 + $ RUBYOPT="--enable-yjit" ruby test.rb 1000 24 + 1000 * 940 = 940000 records in 13.457106019 -> 69851.57125706079 records/s 25 + ```