Re: On disable_cost

Thomas Munro <thomas(dot)munro(at)gmail(dot)com> writes:
> On Wed, Dec 11, 2019 at 7:24 PM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> wrote:
>> Doesn't that rely on a specific implementation of double precision (IEEE)?
>> I thought that we don't want to limit ourselves to platforms with IEEE floats.

> Just by the way, you might want to read the second last paragraph of
> the commit message for 02ddd499. The dream is over, we're never going
> to run on Vax.

Still, the proposed hack is doubling down on IEEE dependency in a way
that I quite dislike, in that (a) it doesn't just read float values
but generates new ones (and assumes that the hardware/libc will react in
a predictable way to them), (b) in a part of the code that has no damn
business having close dependencies on float format, and (c) for a gain
far smaller than what we got from the Ryu code.

We have had prior discussions about whether 02ddd499 justifies adding
more IEEE dependencies elsewhere. I don't think it does. IEEE 754
is not the last word that will ever be said on floating-point arithmetic,
any more than x86_64 is the last CPU architecture that anyone will ever
care about. We should keep our dependencies on it well circumscribed.

regards, tom lane