Re: [9fans] comparisons with NaN

[erik quanstrom <quanstro@quanstro.net>]

amd64 does yet something else.

amd64	(a == b) (a >= b) (a > b) (b == a) (b >= a) (b > a)
386	(a < b) (a <= b) (a == b) (b < a) (b <= a) (b == a)
arm	(a < b) (a <= b) (a != b) (b < a) (b <= a) (b != a)
mips	(a < b) (a <= b) (a != b) (b < a) (b <= a) (b != a)

> mainly the assumption, in the compiler and linker, that something like this:
> 	if (a < b) f();
> can safely be transformed to this:
> 	if (a >= b) goto skip;
> 	f();
> 	skip:
> Unfortunately if a or b is NaN, the conditional will be false in both cases.
>
> So is this a feature, or a bug that needs fixing?

how about another option, just a bug.

there are other issues with the floating point, including
the fact that -0.0 is transformed both by the compiler, and
by print(2) to 0.0.  ape's printf prints -0.0 correctly.

at least in terms of passing floating point test suites
(like python's) the NaN issue doesn't come up, but the
-0 issue breaks a number of tests.

- erik