[LLVMdev] max/min intrinsics

[Dmitri Gribenko]

On Wed, Dec 5, 2012 at 10:43 PM, Tim Northover <t.p.northover at gmail.com> wrote:
>> It seems inevitable.  For the floating point version, please make it very
>> clear what the behavior of max(-0,+0) and related cases are.
>
> Along these lines, AArch64 has an instruction "FMAXNM". It returns the
> maximum if neither value is NaN, but returns the number if just one
> value is NaN. This is in addition to an "FMAX" which propagates NaNs.
>
> I suspect you'll just want to consider this as an "oh yes, make sure
> that the result is NaN if either input is" advisory notice, but I
> haven't actually thought through the details of implementation yet.

Given the recent fast-math flags commit, what about the inverse?  ("I
guarantee that inputs are not NaNs")  In this regard min/max look like
other floating point instructions to me.  Does it make sense to add
them as instructions so that they can profit from fast-math flags?

Dmitri

-- 
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
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