__restrict

[Robert Jacques]

On Wed, 19 Oct 2011 17:10:55 -0400, Peter Alexander <peter.alexander.au at gmail.com> wrote:

> On 19/10/11 3:08 PM, Robert Jacques wrote:
>> On Wed, 19 Oct 2011 07:58:15 -0400, Manu <turkeyman at gmail.com> wrote:
>>> I agree, that is certainly more important :)
>>>
>>> I'm mainly just curious to know about how the main contributors feel
>>> about
>>> these things, and whether these things will be implemented/planned, or if
>>> they violate some fundamental language principles...
>>> Basically, I really want to start some major work in D, but before
>>> investing
>>> into the language, I want to know that important features are
>>> recognised and
>>> have a long term plan...
>>
>> Well, __restrict was mainly added to C (IIRC), to allow loop
>> vectorization. In D, we have explicit array operations, which carry a
>> lot of the same caveats as __restrict, except are checkable.
>
> It's for far more than vectorization. Any place that has redundant loads
> can benefit from __restrict.
>
> I recommend this presentation on the subject:
> http://www.slideshare.net/guest3eed30/memory-optimization
>
> It's about memory optimizations. Aliasing issues start at slide 35.
>

Thanks. I've seen most of that before. And even in those slide, the major (though not only) use-case for __restrict is with array and matrix processing. Most other use-cases can be cached manually or are really, really unsafe.