llvm dev - May 2015 - [LLVMdev] how to do make a FP_ROUND need/operattion

Hi Guys,

I and trying to covert a float to a f16.
calling


 DAG.getNode(ISD::FP_ROUND, DL, Op->getValueType(0), FloatNode);


will get the error message:"Invalid method to make FP_ROUND node"


what is the "right" way to make this work?


best

Kevin
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The problem is that FP_ROUND has two operands, per ISDOpcodes.h:

-Ahmed


On Mon, May 11, 2015 at 5:26 PM, Zhang, Kewu <Kewu.Zhang at amd.com>
wrote:
> Hi Guys,
>
> I and trying to covert a float to a f16.
> calling
>
>  DAG.getNode(ISD::FP_ROUND, DL, Op->getValueType(0), FloatNode);
>
>
> will get the error message:"Invalid method to make FP_ROUND node"
>
>
> what is the "right" way to make this work?
>
>
> best
>
> Kevin
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>

On Mon, May 11, 2015 at 6:46 PM, Ahmed Bougacha
<ahmed.bougacha at gmail.com> wrote:
> The problem is that FP_ROUND has two operands, per ISDOpcodes.h:
    /// X = FP_ROUND(Y, TRUNC) - Rounding 'Y' from a larger floating
point type
    /// down to the precision of the destination VT.  TRUNC is a flag, which is
    /// always an integer that is zero or one.  If TRUNC is 0, this is a
    /// normal rounding, if it is 1, this FP_ROUND is known to not change the
    /// value of Y.

So, something like this should work:

    DAG.getNode(ISD::FP_ROUND, DL, Op->getValueType(0), FloatNode,
DAG.getIntPtrConstant(0, DL));

-Ahmed
> -Ahmed
>
>
> On Mon, May 11, 2015 at 5:26 PM, Zhang, Kewu <Kewu.Zhang at amd.com>
wrote:
>> Hi Guys,
>>
>> I and trying to covert a float to a f16.
>> calling
>>
>>  DAG.getNode(ISD::FP_ROUND, DL, Op->getValueType(0), FloatNode);
>>
>>
>> will get the error message:"Invalid method to make FP_ROUND
node"
>>
>>
>> what is the "right" way to make this work?
>>
>>
>> best
>>
>> Kevin
>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>