OT (partially): about promotion of integers

[foobar]

On Wednesday, 12 December 2012 at 10:35:26 UTC, Walter Bright 
wrote:
> On 12/12/2012 2:33 AM, foobar wrote:
>> This isn't a perfect solutions
>> since the compiler has builtin knowledge about int and does 
>> optimizations that
>> will be lost with a library type.
>
> See my reply to bearophile about that.

Yeah, just saw that :)
So basically you're suggesting to implement Integer and Word 
library types using compiler intrinsics as a way to migrate to 
better ML compatible semantics. This is a possible solution if it 
can be proven to work.

Regarding performance and overflow checking, the example you give 
is x86 specific. What about other platforms? For example ARM is 
very popular nowadays in the mobile world and there are many more 
smart-phones out there than there are PCs. Is the same issue 
exists and if not (I suspect not, but really have no idea) should 
D be geared towards current platforms or future ones?