StringComparison.Ordinal same as not specified calls?

[benaadams]

Should string.IndexOf(..., StringComparison.Ordinal) go via SpanHelpers rather than CompareInfo.Invariant.IndexOf?

[jkotas]

I think so, assuming that it is uniformly faster.

There seems to be a lot of redundancies and inefficiencies along these paths, e.g.:

• public static int IndexOf(this ReadOnlySpan<char> span, ReadOnlySpan<char> value, StringComparison comparisonType) should go via SpanHelpers for ordinal too
• // TODO: Instead of this method could we just have upstack code call IndexOfOrdinal with ignoreCase = false?
• Uses of IsFastSort() in IndexOf can be replaced with fast loop like we have done elsewhere

[GrabYourPitchforks]

This appears to have already been addressed. Please reopen if this was closed in error.