[llvm-dev] creating Intrinsic DAG Node

[Ryan Taylor via llvm-dev]

Matt,

 Thanks for the response. Is there an example in the code somewhere of
doing the intrinsic ID method? I don't need to put it a lot of places so
I'm not sure it warrants adding a node.

Thanks.

On Tue, Feb 2, 2016 at 12:35 PM, Matt Arsenault <arsenm2 at gmail.com> wrote:

>
> > On Feb 2, 2016, at 09:29, Ryan Taylor via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
> >
> > I'm trying to 'lower' an operation that needs to create a node in the SD
> that is an intrinsic call.... what is the best way to do this?
> >
> > I see in the DAGBuilder it calls 'setValue' which adds to the map
> NodeMap[V] where V is the key and the passed in SDValue is the value but
> I'm not sure this is a good way to do it since these are local to
> SelectionDAGBuilder and the lowering needs to happen in XXXISelLowering.cpp.
> >
> > Thanks.
> > _______________________________________________
> > LLVM Developers mailing list
> > llvm-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
> SelectionDAGBuilder creates INTRINSIC_W_CHAIN, INTRINSIC_WO_CHAIN, or
> INTRINSIC_VOID nodes. You want to emit those with the intrinsic ID as a
> TargetConstant the first operand (or second with chains). I would recommend
> though for these cases, if you want to emit emit them in the backend, it’s
> a bit nicer to lower these to a custom node, and select on that. It’s a bit
> nicer than having to add the intrinsic ID everywhere. Most of the AMDGPU
> intrinsics are handled this way.
>
> -Matt
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160202/50109d1a/attachment.html>