Commits on Sep 16, 2024

1. Fix RegexOptions.Compiled|IgnoreCase perf when dynamic code isn't sup… …

   …ported
   
   If a regex is created with RegexOptions.Compiled and RegexOptions.IgnoreCase, and it begins with a pattern that's a reasonably small number of alternating strings, it'll now end up using `SearchValues<string>` to find the next possible match location. However, the `SearchValues<string>` instance doesn't end up getting created if the interpreter is being used. If the implementation falls back to the interpreter because compilation isn't supported because dynamic code isn't supported, then it won't use any optimizations to find the next starting location. That's a regression from when it would previously at least use a vectorized search to find one character class from the set of starting strings.
   
   This fixes it to just always create the `SearchValues<string>`. This adds some overhead when using RegexOptions.Compiled, but it's typically just a few percentage points, and only applies in the cases where this `SearchValues<string>` optimization kicks in. At the moment, changing it to have perfect knowledge about whether it can avoid that creation is too invasive. This overhead also doesn't apply to the source generator.

   

   stephentoub committed Sep 16, 2024
   Configuration menu

   • View commit details
   • Copy full SHA for 542f8eb
   • Browse repository at this point

   Copy the full SHA

   542f8eb View commit details

   Browse the repository at this point in the history