std.math performance (SSE vs. real)

[John Colvin via Digitalmars-d]

On Sunday, 29 June 2014 at 19:22:16 UTC, Walter Bright wrote:
> On 6/29/2014 11:21 AM, Russel Winder via Digitalmars-d wrote:
>> Because when reading the code you haven't got a f####### clue 
>> how
>> accurate the floating point number is until you ask and answer 
>> the
>> question "and which processor are you running this code on".
>
> That is not  true with D. D specifies that float and double are 
> IEEE 754 types which have specified size and behavior. D's real 
> type is the largest the underlying hardware will support.
>
> D also specifies 'int' is 32 bits, 'long' is 64, and 'byte' is 
> 8, 'short' is 16.

I'm afraid that it is exactly true if you use `real`.

What important use-case is there for using `real` that shouldn't 
also be accompanied by a `static assert(real.sizeof >= 10);` or 
similar, for correctness reasons?

Assuming there isn't one, then what is the point of having a type 
with hardware dependant precision? Isn't it just a useless 
abstraction over the hardware that obscures useful intent?

mixin(`alias real` ~ (real.sizeof*8).stringof ~ ` = real;`);

is more useful to me.