Special-case two set loops in RegexCompiler #32003
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danmoseley
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...libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexCompiler.cs
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...ibraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexCharClass.cs
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eerhardt
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src/libraries/System.Text.RegularExpressions/tests/Regex.Groups.Tests.cs
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When RegexOptions.Singleline is specified, `.*` goes from meaning `[^\n]*` to meaning `[everything]*`. As such, when we encounter it, we can just jump to the end without actually comparing anything. This is worth optimizing in in the compiler because, well, why not, but we don't in the interpreter because it's not a common-enough pattern to spend cycles checking for.
Co-Authored-By: Dan Moseley <danmose@microsoft.com>
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.*and RegexOptions.Singleline was specified, it ends up meaning[everything]*, in which case we don't have to match anything and can just jump to the last position.[^xyz]*with 2 or 3 negated chars in a set loop, we can use IndexOfAny for those chars to vectorize the search.Contributes to #1349
cc: @danmosemsft, @eerhardt, @ViktorHofer