Why don't we switch to C like floating pointed arithmetic instead of automatic expansion to reals?

[David Nadlinger via Digitalmars-d]

On Saturday, 6 August 2016 at 09:35:32 UTC, Walter Bright wrote:
> The LDC fastmath bothers me a lot. It throws away proper NaN 
> and infinity handling, and throws away precision by allowing 
> reciprocal and algebraic transformations.

This is true – and precisely the reason why it is actually 
defined (ldc.attributes) as

---
alias fastmath = AliasSeq!(llvmAttr("unsafe-fp-math", "true"), 
llvmFastMathFlag("fast"));
---

This way, users can actually combine different optimisations in a 
more tasteful manner as appropriate for their particular 
application.

Experience has shown that people – even those intimately familiar 
with FP semantics – expect a catch-all kitchen-sink switch for 
all natural optimisations (natural when equating FP values with 
real numbers). This is why the shorthand exists.

  — David