Consider marking functions `constexpr` about simde HOT 4 CLOSED

In my original post on SO, I intend to use SIMD in an overloaded operator function to add two mathematical vectors together. Although this makes the addition fast at runtime, since I'm using SIMD in these functions, I cannot use the operators with constexpr variables. This forces simply evaluabe vectors that are comprised of some combination of expressions using these overloaded operators to be evaluated at runtime, which is not optimal.

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I understand what constexpr does, and what you're trying to do. What I'm trying to figure out is whether there is really a practical application, or do you just think it would be a cool feature (which I agree with, but I don't think is enough of a reason to justify the amount of effort involved).

People don't generally have a lot of data available at compile-time, and if you do you should probably be pre-processing it instead of relying on the compiler and constexpr. So the only time I can really see this coming in handy is if you have a very hot loop that changes depending on a compile-time parameter in a non-trivial way, which isn't something I see in the wild very often at all.

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I just realized that may have sounded a bit snarky, which isn't what I intended. I think this is an interesting idea, I'm just having trouble thinking of a reason you would want to do what you described that wouldn't be better addressed by a different solution.

If there is something I'm missing I'd definitely consider implementing this, I just don't want to do something that would add a lot of complexity to SIMDe without a good reason.

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I'm going to close this, but I'm still open to the idea if anyone can convince me that it's worth the additional complication.

In the meantime, maybe Iris might be more open to this? The depend pretty heavily on templates so you wouldn't need to modify nearly as many places as for SIMD. Unfortunately they don't have the code that SIMDe does for accelerating one ISA extension with another, or AFAIK even a native implementation (though I could be wrong about that part).

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