CallSites for MemoryExtensions.Contains (CoreCLR)

[grant-d]

• See https://github.com/dotnet/corefx/issues/27526 : Contains is optimized over IndexOf
• Found additional (~12) callsites that can take advantage of Span<T>.Contains
• Extension method does not need to be unsafe

[ahsonkhan]

Missed one:

coreclr/src/System.Private.CoreLib/shared/System/String.Searching.cs

Line 27 in 91820bd

return IndexOf(value) != -1;

Otherwise, LGTM. Thanks :)

[grant-d]

@ahsonkhan, not sure what you are proposing with that one - it is an instance method on string, and delegates to string.IndexOf not Span<T>.IndexOf. Unless you are proposing I use string.AsSpan<char>.Contains?

[ahsonkhan]

Unless you are proposing I use string.AsSpan<char>.Contains?

No, that isn't what I was suggesting.

not sure what you are proposing with that one - it is an instance method on string, and delegates to string.IndexOf not Span<T>.IndexOf

Right now public bool Contains(char value) is calling the following, which ends up calling the SpanHelpers static method:

coreclr/src/System.Private.CoreLib/shared/System/String.Searching.cs

Line 38 in 91820bd

public int IndexOf(char value) => SpanHelpers.IndexOf(ref _firstChar, value, Length);

Is it possible for it to instead call the following, directly?

coreclr/src/System.Private.CoreLib/shared/System/SpanHelpers.Char.cs

Line 80 in f9c2e89

public static unsafe bool Contains(ref char searchSpace, char value, int length)

So, something like:

        public bool Contains(char value) => SpanHelpers.Contains(ref _firstChar, value, Length);

[grant-d]

Sorry, must be a Friday, that makes sense.
PR updated.

[ahsonkhan]

@dotnet-bot test Ubuntu x64 Checked CoreFX Tests

[jkotas]

@dotnet-bot test Ubuntu x64 Checked CoreFX Tests

[grant-d]

@ahsonkhan would you mind taking another look at this, I have added a couple more call sites since your previous approval so it would be great if you could confirm it's kosher (& hopefully merge it)?