OT (partially): about promotion of integers

[eles]

On Wednesday, 12 December 2012 at 14:39:40 UTC, Michael wrote:
> Machine/hardware have a explicitly defined register size and 
> does know nothing about sign and data type. fastest operation 
> is unsigned and fits to register size.

Frankly, the hardware knows nothing about classes and about 
virtual methods, neither.

The question is: why the DEVELOPER should know about that 
register size? There are many other things that the developer is 
unaware of (read SSE instructions) and those are optimized behind 
his back.

The choice to promote to the fastest type is a sweet thing for 
the compiler, but a burden for the developer.

OTOH, I *never* asked for compulsory promotion, just mimicking 
it. (in fact, I was not asking for anything, just addressed a 
question) The idea is to guarantee, by the compiler, that the 
final result of an integral arithmetic expression is AS IF all 
integrals there are promoted to some widest-integral type.

Actual promotion would be made only if the compiler believes 
that's really necessary.

In the current implementattion too, speed is lost as long as you 
have a long there, as you need promotion further than int.