Runtime: Consider optimizing Span IndexOf for OrdinalIgnoreCase (portable span)

[ahsonkhan]

This is specific to portable span (and not fast span).

We do not necessarily need to allocate and call the string APIs when StringComparison is OrdinalIgnoreCase for IndexOf.

See https://github.com/dotnet/corefx/pull/28239#issue-176098021 for details and a proposed implementation of IndexOfOrdinalIgnoreCase as a starting point.

We would need to test and measure to make sure there isn't significant regression for certain cases as part of the optimization for the common/general case.

[MarcoRossignoli]

This is specific to portable span (and not fast span).

To test/measure portable do you mean compile -framework=netfx?

We would need to test and measure to make sure there isn't significant regression for certain cases as part of the optimization for the common/general case.

Do you mean create e new benchmark on System.Memory.Performance.Tests using this guide?

[AlexRadch]

I am working on it.

[MarcoRossignoli]

@AlexRadch maybe you can answer to my question, to test "portable" code do you use netfx switch?

[stephentoub]

test "portable" code do you use netfx switch?

That's what I do. More specifically, after doing a full build with -framework=netfx, then iterating with /p:TargetGroup=netfx with the project src and tests.

[MarcoRossignoli]

@stephentoub thank's!

[ahsonkhan]

More specifically, after doing a full build with -framework=netfx, then iterating with /p:TargetGroup=netfx with the project src and tests.

You can build and run the unit tests this way, but does the same apply to running performance tests?

[ahsonkhan]

I am working on it.

Assigning the issue.