AVX for math code ... avx instructions later disappearing ?

[kinke]

On Sunday, 26 September 2021 at 18:08:46 UTC, james.p.leblanc 
wrote:
> or even moving the array declarations to before
> the dot product function, and the avx instructions will 
> disappear!

That's because the `@fastmath` UDA applies to the next 
declaration only, which is the `x` array in your 2nd example 
(where it obviously has no effect). Either use `@fastmath:` with 
the colon to apply it to the entire scope, or use `-ffast-math` 
in the LDC cmdline.

Similarly, when moving the function to another module and you 
don't include that module in the cmdline, it's only imported and 
not compiled and won't show up in the resulting assembly.

Wrt. stack alignment, there aren't any issues with LDC AFAIK (not 
limited to 16 or whatever like DMD).