Enable SymbolicRegexNode.IsNullableFor fast path to inline

[stephentoub]

Method	Toolchain	Mean	Error	StdDev	Ratio	RatioSD	Allocated
IsMatch	\main\corerun.exe	10.639 ms	0.0453 ms	0.0402 ms	1.00	0.00	-
IsMatch	\pr\corerun.exe	9.190 ms	0.1800 ms	0.2143 ms	0.87	0.02	-

usingBenchmarkDotNet.Attributes;usingBenchmarkDotNet.Diagnosers;usingBenchmarkDotNet.Running;usingSystem.Linq;usingSystem.Text.RegularExpressions;[MemoryDiagnoser]publicpartialclassProgram{publicstaticvoidMain(string[]args){BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).Run(args);}privateRegex_regex=newRegex("[a-q][^u-z]{13}x",RegexOptions.NonBacktracking);privatestring_input=string.Concat(Enumerable.Repeat("abcdefghijklz",100_000));[Benchmark]publicboolIsMatch()=>_regex.IsMatch(_input);}

[ghost]

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Issue Details

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Method	Toolchain	Mean	Error	StdDev	Ratio	RatioSD	Allocated
IsMatch	\main\corerun.exe	10.639 ms	0.0453 ms	0.0402 ms	1.00	0.00	-
IsMatch	\pr\corerun.exe	9.190 ms	0.1800 ms	0.2143 ms	0.87	0.02	-

usingBenchmarkDotNet.Attributes;usingBenchmarkDotNet.Diagnosers;usingBenchmarkDotNet.Running;usingSystem.Linq;usingSystem.Text.RegularExpressions;[MemoryDiagnoser]publicpartialclassProgram{publicstaticvoidMain(string[]args){BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).Run(args);}privateRegex_regex=newRegex("[a-q][^u-z]{13}x",RegexOptions.NonBacktracking);privatestring_input=string.Concat(Enumerable.Repeat("abcdefghijklz",100_000));[Benchmark]publicboolIsMatch()=>_regex.IsMatch(_input);}

Author:	stephentoub
Assignees:	-
Labels:	area-System.Text.RegularExpressions
Milestone:	7.0.0

[joperezr]

Code change looks good to me.