Consider updating Math.Clamp to not throw when min is greater than max

[jeffhandley]

As noted by @tannergooding:

It's pretty typical for Clamp APIs to follow a well-specified order for mismatched min/max, as it's far more efficient and is useful for a number of scenarios. -- We end up doing just this for the vector APIs and it correspondingly can bleed into other scenarios, like Tensors

The typical behavior is Min(Max(value, min), max) which matches what hardware typically does for such instructions, what HLSL and GLSL do, etc. -- Effectively this returns max if min/max are incorrectly ordered.

Default behavior (min/max are correctly ordered)

value	min	max	result
1	2	3	2
2	1	3	2
3	1	2	2

Swapped behavior (Min(Max(value, min), max))

value	min	max	result
1	3	2	2
2	3	1	1
3	2	1	1

Swapped behavior (Max(Min(value, max), min))

value	min	max	result
1	3	2	3
2	3	1	3
3	2	1	2

Originally posted by @tannergooding in #118824 (comment)

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[xtqqczze]

Diffs:

• [JitDiff X64] xtqqczze/dotnet-runtime/math-clamp MihuBot/runtime-utils#1396
• [JitDiff ARM64] xtqqczze/dotnet-runtime/math-clamp MihuBot/runtime-utils#1397

[xtqqczze]

We should also consider the same change in:

• BigInteger.Clamp(BigInteger, BigInteger, BigInteger) Method
• INumber<TSelf>.Clamp(TSelf, TSelf, TSelf) Method
• INumber<TSelf>.ClampNative(TSelf, TSelf, TSelf) Method

[xtqqczze]

If these methods are to continue to throw, we should also consider whether they should throw if min or max is NaN.

[PavelCibulka]

I’d stop throwing exception.

I doubt anyone has written code that relies on Clamp throwing when min and max are in the wrong order. A simple Roslyn analyzer for obvious mistakes would be enough.

[xtqqczze]

I doubt anyone has written code that relies on Clamp throwing when min and max are in the wrong order. A simple Roslyn analyzer for obvious mistakes would be enough.

Perhaps we could use RuntimeHelpers.IsKnownConstant to throw if it can be determined at compile time that min and max are mismatched.

[tannergooding]

Perhaps we could use RuntimeHelpers.IsKnownConstant to throw if it can be determined at compile time that min and max are mismatched.

Having the behavior differ between constant and non-constant is a non-starter. You could have an analyzer try to flag it, but its pretty unlikely someone will get it messed up; especially in a way that isn't caught by simples tests.