Vector512 Support for Enumerable<int>.Min/Max

[Spacefish]

Use the new Vector512 type introduced in NET 8, when

• enough elements
• hardware support is present

to calculate Enumerable.Min() and Enumerable.Max()

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Issue Details

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Use the new Vector512 type introduced in NET 8, when

• enought elements
• hardware support is present
• we are executing in .NET 8

to calculate Enumerable.Min() and Enumerable.Max()

Author:	Spacefish
Assignees:	-
Labels:	area-System.Linq, community-contribution
Milestone:	-

[eiriktsarpalis]

Would it be possible to increase the maximum length for Min and Max test data so that the Vector512 code path is better tested?

https://github.com/stephentoub/runtime/blob/710657575ffbc7de90c345239dc92ce52a9a2558/src/libraries/System.Linq/tests/MaxTests.cs#L14

https://github.com/stephentoub/runtime/blob/710657575ffbc7de90c345239dc92ce52a9a2558/src/libraries/System.Linq/tests/MinTests.cs#L14

[Spacefish]

@eiriktsarpalis i increased them to 65, so we are at least 1 element wider even for byte than the Vector512.

This lead to problems with the sybte type, as the test internally does source.Max(x => x + T.One) which leads to an overflow in sbyte and adds a "-128" element.
The .Max function behaves correctly and return the element "1272 as the max element but the Test Assertion compares it to the now wrongly overflown expected value of "-128".

I therefore added some code to not generate any testdata for the sybte type which is larger than 126 (length < sybte.MaxValue).

[BruceForstall]

cc @dotnet/avx512-contrib