Let's kill 80bit real at CTFE

[tsbockman via Digitalmars-d]

On Friday, 9 September 2016 at 11:50:08 UTC, Stefan Koch wrote:
> Hi,
>
> In short 80bit real are a real pain to support cross-platform.
> emulating them in software is prohibitively slow,

Supposedly, well-optimized 128-bit software floating-point is 
actually a bit faster than hardware 80-bit. (Intel keeps 80-bit 
around primarily for backwards compatibility, and hasn't put much 
effort or die space into improving its hardware speed in many 
years.)

> and more importantly hard to get right.
> 64bit floating-point numbers are supported on more 
> architectures and are much better supported.
> They are also trivial to use at ctfe.
> I vote for killing the 80bit handling at constant folding.
>
> Destroy!

This has been debated to death in the past. Reducing the maximum 
precision is not an acceptable option, but 80-bit could 
potentially be replaced by a software 128-bit implementation if 
that helps.