llvm dev - Nov 2018 - Proposed new min and max intrinsics

On Thu, 11 Oct 2018 at 00:28, Thomas Lively via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
> I just wanted to bump this to see if anyone has any input. I would really
like to get these landed soon if there are no objections.
Hi Thomas,

With ISD::FMINNAN and ISD::FMAXNAN now easy to produce for any target
due to these newly exposed intrinsics, I think these nodes should be
handled in at least SelectionDAGLegalize::ExpandNode (for when the
float type is legal but the operation is not) and
DAGTypeLegalizer::SoftenFloatResult (for when the float type is not
legal).

Best,

Alex

Sounds good, I'll take a look.

On Thu, Nov 1, 2018 at 9:45 AM Alex Bradbury <asb at asbradbury.org>
wrote:
> On Thu, 11 Oct 2018 at 00:28, Thomas Lively via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
> >
> > I just wanted to bump this to see if anyone has any input. I would
> really like to get these landed soon if there are no objections.
>
> Hi Thomas,
>
> With ISD::FMINNAN and ISD::FMAXNAN now easy to produce for any target
> due to these newly exposed intrinsics, I think these nodes should be
> handled in at least SelectionDAGLegalize::ExpandNode (for when the
> float type is legal but the operation is not) and
> DAGTypeLegalizer::SoftenFloatResult (for when the float type is not
> legal).
>
> Best,
>
> Alex
>
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Alex,

After looking into this a bit, it looks to me like the best thing to do for
targets that do not natively support ISD::MINIMUM and ISD::MAXIMUM would be
to fall back to a libcall, since implementing these operations in terms of
existing operations is actually rather complicated. Do you think it would
make sense to add builtin functions to compiler-rt to implement these
operations, or is there a better way of handling this?

Thanks,

Thomas

On Thu, Nov 1, 2018 at 11:49 AM Thomas Lively <tlively at google.com>
wrote:
> Sounds good, I'll take a look.
>
> On Thu, Nov 1, 2018 at 9:45 AM Alex Bradbury <asb at asbradbury.org>
wrote:
>
>> On Thu, 11 Oct 2018 at 00:28, Thomas Lively via llvm-dev
>> <llvm-dev at lists.llvm.org> wrote:
>> >
>> > I just wanted to bump this to see if anyone has any input. I would
>> really like to get these landed soon if there are no objections.
>>
>> Hi Thomas,
>>
>> With ISD::FMINNAN and ISD::FMAXNAN now easy to produce for any target
>> due to these newly exposed intrinsics, I think these nodes should be
>> handled in at least SelectionDAGLegalize::ExpandNode (for when the
>> float type is legal but the operation is not) and
>> DAGTypeLegalizer::SoftenFloatResult (for when the float type is not
>> legal).
>>
>> Best,
>>
>> Alex
>>
>
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