On 10/23/2013 9:22 AM, David Nadlinger wrote:
On Wednesday, 23 October 2013 at 16:15:56 UTC, Walter Bright wrote:
A D compiler is allowed to compute floating point results at arbitrarily large
precision - the storage size (float, double, real) only specify the minimum
precision.
This behavior is fairly deeply embedded into the front end, optimizer, and
various back ends.
I know we've had this topic before, but just for the record, I'm still not sold
on the idea of allowing CTFE to yield different results than runtime execution.
Java initially tried to enforce a maximum precision, and it was a major disaster
for them. If I have been unable to convince you, I suggest reviewing that case
history.
Back when I designed and built digital electronics boards, it was beaten into my
skull that chips always get faster, never slower, and the slower parts routinely
became unavailable. This means that the circuits got designed with maximum
propagation delays in mind, and with a minimum delay of 0. Then, when they work
with a slow part, they'll still work if you swap in a faster one.
FP precision is the same concept. Swap in more precision, and your correctly
designed algorithm will still work.
