Comment by cjhanks

Yes, SIMD intrinsic programming is often worthless unless implemented for every target architecture. Let me give you an example case; my target production architecture rarely changes, but I want my program to run on every developer computer where CPUs are heterogeneous.

Now, I think the problem is that it is tying optimizations to instructions rather than CPU architectures. When I ported code from an I7 to an I9 it seemed that instruction latency changed. Still, if you are only supporting limited computational targets any hooks at all help.

But why intrinsic rather than assembly? Because usually vector extensions in GCC work well enough, and when they don't intrinsics are easier for me (a man who rarely needs to write assembly and doesn't have the time to beat the compiler in 99.99% of cases).

And a minor point... I really wish GCC had a pragma which allowed me to specify a function should be optimized to multiple targets and then install the thunks automatically.