[llvm-dev] creating Intrinsic DAG Node

[via llvm-dev]

The intrinsic ID is an int, not a float.

—escha

> On Jun 24, 2016, at 7:49 AM, Ryan Taylor via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> given the following C code:
> 
> float b=16, a=0;
> int main() {
>    float a = sqrt(b);
>    return0;
> }
> 
> I'm trying to lower FSQRT down, but getting a casting issue, my code is:
> 
> SDValue XXXLowering::LowerFSQRT(SDValue Op, SelectionDAG &DAG) const {
>    SDLoc DL(Op);
>    EVT VT = Op.getValueType();
>    SDValue LHS = Op.getOperand(0);
> 
>    SDValue newNode = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, VT, DAG.getTargetConstantFP(Intrinsic::my_intrinsic, DL, VT), LHS);
>    return newNode;
> }
> 
> The error I'm getting is: Assertion 'isa<X>(Val) && "cast<Ty>() argument of incompatible type!"
> 
> Is this the correct way to add intrinsic dag node?
> 
> Thanks.
> 
> 
> On Tue, Feb 2, 2016 at 5:10 PM, Ryan Taylor <ryta1203 at gmail.com <mailto:ryta1203 at gmail.com>> wrote:
> Matt,
> 
>   The added intrinsic in DAG looks like:
> 
> 0xbedb698: i32 = llvm.MyIntrinsic 0xbedb200, 0xbedac18 [ORD=4]
> 
>   The builtin in DAG looks like:
> 
> 0xbedb2a8: i32,ch = llvm 0xbedb158:1, 0xbedb200, 0xbedb158 [ORD=7] [ID=16]
> 
>    The only difference I'm seeing is the extra operand, which is a 'ch' from a load.
> 
> On Tue, Feb 2, 2016 at 3:55 PM, Matt Arsenault <arsenm2 at gmail.com <mailto:arsenm2 at gmail.com>> wrote:
> 
> > On Feb 2, 2016, at 12:43, Ryan Taylor <ryta1203 at gmail.com <mailto:ryta1203 at gmail.com>> wrote:
> >
> > Matt,
> >
> >   This seems to generate llvm.my_intrinsic just fine in the DAG, so no DAG errors; however, it won't match. For example, if I call the intrinsic from C, the DAG node looks to be named the same in dotty file but it won't match... am I missing something?
> >
> >   I've done it exactly the way it was done above. The DAG looks great but it won't match. Did I miss something?
> >
> > Thanks.
> >
> 
> Are you using the right intrinsic type? Does it have a chain or result?
> 
> How are you calling it from C? Are you declaring the intrinsic? This can fail if you mismatched the readnone or readonly to the actual intrinsic definition
> 
> 
> 
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