Differences in results when using the same function in CTFE and Runtime

[Timon Gehr]

On 8/8/24 12:31, Carsten Schlote wrote:
> 
> And it opens up some questions:
> 
> - Can CTFE be used under all circumstances when float numbers of any 
> precision are involved?
> - Or is this some kind of expected behaviour whenever floats are involved?
> - Is the D CTFE documentation completely covering such possible issues?
> 
> I can imagine that bugs causes by such subtil differences might be very 
> difficult to fix.
> 
> 
> Any experiences or thought on this?

The specification allows behavior like that even at runtime.
https://dlang.org/spec/float.html

I have been vocally against this. Full portability is perhaps one thing, 
as hardware differences do exist, but completely thwarting the 
expectations by deliberately doing a different operation than the one 
you requested I think makes no sense at all. A lot of modern hardware 
nowadays is compatible or almost compatible regarding floats.