Displaying 2 results from an estimated 2 matches for "nan_swallowing_fmin".
2014 Sep 13
2
[LLVMdev] [PATCH][RFC]: Add fmin/fmax intrinsics
...D GPUs that Matt cares about
> support it, and PTX has native operations for it as well. The IR expansion
> of an IEEE-conforming fmin/fmax is at least three compares + selects, which
> makes it very difficult to pattern match for these targets.
>
It's 2 compares + selects:
float nan_swallowing_fmin(float a, float b) {
return b != b ? a : (a < b ? a : b);
}
which is within the realm of pattern-matching.
>
> The inverse form (always propagating NaNs) is not widely natively
> supported.
>
> I think AArch64 *might* have it?
>
It does. In fact, even armv7 has a NaN-pr...
2014 Sep 12
2
[LLVMdev] [PATCH][RFC]: Add fmin/fmax intrinsics
> On Sep 12, 2014, at 10:27 AM, Dan Gohman <dan433584 at gmail.com> wrote:
>
>
> More generally, I don’t see a compelling reason for LLVM to add intrinsic support for the version you’re proposing. Your choice can easily be expanded into IR, and does not have the wide hardware support (particularly in GPUs) that the IEEE version does.
>
> The IEEE version can also be