core.traits?

[Mike Franklin]

On Wednesday, 9 January 2019 at 19:24:28 UTC, Jacob Carlborg 
wrote:

>> Yes, it's possible, but I don't think it will ever be accepted 
>> if it doesn't perform at least as well as the optimized 
>> versions in C or assembly that use AVX512 or other SIMD 
>> features.  It needs to be at least as good as what libc 
>> provides, so we need to be able to leverage these unique 
>> hardware features to get the best performance.
>
> Perhaps it could be considered as a fallback when a "memcpy" 
> isn't available.

I'm not sure what you mean. DMD currently links in libc, so 
`memcpy` is always available.

Also, it's difficult for me to articulate, but we don't want 
`void* memcpy(void* destination, const void* source, size_t num)` 
rewritten in D.  We need `void memcpy(T)(T* destination, const T* 
source)` or some other strongly typed template like that. And as 
an aside, thanks to https://github.com/dlang/dmd/pull/8504 we now 
have to be careful about the order of arguments.

Anyway, I'm not sure there's much point in hashing this out right 
now.  We need dynamic stack allocation first before any of this 
can happen because the runtime hooks need to be able to generate 
dynamic assertion messages in -betterC, and there's only one 
person I know of that can do that (Walter), and I don't think 
it's a priority for him right now.

Mike