Improve IndexOf(char, OrdinalIgnoreCase)

[EgorBo]

A similar trick is used for IndexOf(string, OrdinalIgnoreCase) see here.

Benchmark:

usingBenchmarkDotNet.Attributes;usingBenchmarkDotNet.Running;BenchmarkSwitcher.FromAssembly(typeof(Benchmarks).Assembly).Run(args);publicclassBenchmarks{conststringTestStr=".NET Runtime uses third-party libraries or other resources that may be"+" distributed under licenses different than the.NET Runtime software.";[Benchmark]publicintIndexOfDash()=>TestStr.IndexOf('-',StringComparison.OrdinalIgnoreCase);[Benchmark]publicintIndexOfL()=>TestStr.IndexOf('L',StringComparison.OrdinalIgnoreCase);[Benchmark]publicintIndexOfZ()=>TestStr.IndexOf('z',StringComparison.OrdinalIgnoreCase);}

Method	Job	Toolchain	Mean	Ratio
IndexOfDash	Job-GBURIF	\Core_Root_base\corerun.exe	16.125 ns	1.00
IndexOfDash	Job-DLWGWE	\Core_Root\corerun.exe	7.084 ns	0.44
IndexOfL	Job-GBURIF	\Core_Root_base\corerun.exe	14.907 ns	1.00
IndexOfL	Job-DLWGWE	\Core_Root\corerun.exe	5.630 ns	0.38
IndexOfZ	Job-GBURIF	\Core_Root_base\corerun.exe	16.809 ns	1.00
IndexOfZ	Job-DLWGWE	\Core_Root\corerun.exe	8.337 ns	0.50

[ghost]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[stephentoub]

Thanks.

[ghost]

Tagging subscribers to this area: @dotnet/area-system-runtime
See info in area-owners.md if you want to be subscribed.

Issue Details

---

A similar trick is used for IndexOf(string, OrdinalIgnoreCase) see here.

Benchmark:

usingBenchmarkDotNet.Attributes;usingBenchmarkDotNet.Running;BenchmarkSwitcher.FromAssembly(typeof(Benchmarks).Assembly).Run(args);publicclassBenchmarks{conststringTestStr=".NET Runtime uses third-party libraries or other resources that may be"+" distributed under licenses different than the.NET Runtime software.";[Benchmark]publicintIndexOfDash()=>TestStr.IndexOf('-',StringComparison.OrdinalIgnoreCase);[Benchmark]publicintIndexOfL()=>TestStr.IndexOf('L',StringComparison.OrdinalIgnoreCase);[Benchmark]publicintIndexOfZ()=>TestStr.IndexOf('z',StringComparison.OrdinalIgnoreCase);}

Method	Job	Toolchain	Mean	Ratio
IndexOfDash	Job-GBURIF	\Core_Root_base\corerun.exe	16.125 ns	1.00
IndexOfDash	Job-DLWGWE	\Core_Root\corerun.exe	7.084 ns	0.44
IndexOfL	Job-GBURIF	\Core_Root_base\corerun.exe	14.907 ns	1.00
IndexOfL	Job-DLWGWE	\Core_Root\corerun.exe	5.630 ns	0.38
IndexOfZ	Job-GBURIF	\Core_Root_base\corerun.exe	16.809 ns	1.00
IndexOfZ	Job-DLWGWE	\Core_Root\corerun.exe	8.337 ns	0.50

Author:	EgorBo
Assignees:	EgorBo
Labels:	area-System.Runtime
Milestone:	-

[EgorBo]

Failure is #73247