x86 FMA intrinsic support design

[Gilles Duboscq]

Hi Jean-Philippe,

That sounds like a good plan!

In terms of naming, i would call such a node `FusedMultiplyAddNode`: spelling out what it does is much more important than the fact that it comes from an intrinsic.

Thanks,
  Gilles

On 29/03/2019 01:04, Halimi, Jean-Philippe wrote:
> Hello,
> 
> I am currently looking into adding support for FMA intrinsics in Graal. I would like to share what I plan to do to make sure it is how it should be implemented.
> 
> 
> 1.       Add VexRVMOp class support in AMD64Assembler with the corresponding FMA instructions
> 
> a.       It requires to add the VexOpAssertion.FMA and CPUFeature.FMA flags
> 
> 2.       Add UseFMA flag from HotSpot flags in GraalHotSpotVMConfig.java
> 
> 3.       Add a registerFMA method in AMD64GraphBuilderPlugins::registerMathPlugins
> 
> a.       This requires to add a specific FMAIntrinsicNode, which will emit the corresponding FMA instructions.
> 
> Is there anything else that is needed in this case?
> 
> Thanks for your insights,
> Jp
>