std.math performance (SSE vs. real)

[Joseph Rushton Wakeling via Digitalmars-d]

On Thursday, 3 July 2014 at 00:49:33 UTC, Walter Bright wrote:
> On 7/2/2014 2:28 PM, Iain Buclaw via Digitalmars-d wrote:
>> On 2 July 2014 19:58, via Digitalmars-d 
>> <digitalmars-d at puremagic.com> wrote:
>>> I don't really understand the reasoning here. Is D Intel x86 
>>> specific?
>> Yes it is, more than you might realise.  I've been spending 
>> the last 4
>> years breaking it to be platform agnostic. :o)
>
> I think you're conflating dmd with D.
>
> And IEEE 754 is a standard.

I understand what you're saying here, which is that any 
conflation of D with x86 is a fault in the implementation rather 
than the spec, but at the end of the day, D lives by its 
implementation.

It's not just about what the dmd backend supports per se, but 
about what assumptions that leads people to make when writing 
code for the frontend, runtime and standard library.  Iain has 
done some heroic work in the last year going through compiler 
frontend, runtime and Phobos and correcting code with faulty 
assumptions such as "real == 80 bit floating point" (which IIRC 
was often made as a general assumption even though it's 
x86-specific).