I’m not sure I agree on the impossible part, I feel like a sufficiently smart interprocedural analysis that also implements range analysis interprocedurally could prove a lot to where it becomes useful.

I guess what I would like to see is SIMD libraries being able to confidently say nobody needs to use intrinsics (or differentiate between relaxed/normal SIMD on the user API level) because the language + high level SIMD APIs are smart enough to choose the right implementation.

IIRC IEEE min/max with proper NaN handling needs 8 instructions on x86 vs 1 on arm64 I find it very sad that we apparently haven’t really solved that yet without forcing the user to use different APIs.

Anything without range analysis is not worth it.

Note that:

NonZerof32 * NonZerof32 -> NonNanf32

NonZerof32::from_bits(1) multiplied with itself is zero.

Doing range analysis needs the language to support it at compile time, and the dev to specify what range it is.

The only 'stable' thing i can think of is a type for 'greater-eq-one' using only addition and multiplication. Practically every other operation breaks most of the type knowledge up to that point.

You can do it with just 3 instructions for IEEE 754-2019 minimumNumber (ignores NaN):

        vminpd          ymm2, ymm1, ymm0
        vcmpunordpd     ymm0, ymm0, ymm0
        vblendvpd       ymm0, ymm2, ymm1, ymm0

        vminpd          ymm1, ymm0, ymm1
        vbroadcastsd    ymm2, qword ptr [rip + .LCPI0_0]
        vandpd          ymm2, ymm0, ymm2
        vorpd           ymm1, ymm2, ymm1
        vcmpunordpd     ymm2, ymm0, ymm0
        vblendvpd       ymm0, ymm1, ymm0, ymm2

If you want propagating NaNs but don't care about signed zero or NaN payload/sign, you can use

        vminpd  ymm2, ymm0, ymm1
        vminpd  ymm1, ymm1, ymm0
        vorpd   ymm0, ymm1, ymm2

    if (self < other) | self.is_nan() { self } else { other}

        vcmpltpd        ymm2, ymm0, ymm1
        vcmpunordpd     ymm3, ymm0, ymm0
        vorpd           ymm2, ymm3, ymm2
        vblendvpd       ymm0, ymm1, ymm0, ymm2