[PATCH] D37686: [DAG] Consolidating Instruction->SDNode Flags propagation in one class for better code management.

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In https://reviews.llvm.org/D37686#866641, @jbhateja wrote:

> In https://reviews.llvm.org/D37686#866521, @spatel wrote:
>
> > How does this work if an instruction maps to multiple nodes? For example, the FMA intrinsic can map to 2 nodes?
>
>
> This propagation happens during SelectionDAGBuilder::visit, I scanned through various instructions and there is 1:1 mapping b/w instructions and initial SDNode created for it.




  case Intrinsic::fmuladd: {
    EVT VT = TLI.getValueType(DAG.getDataLayout(), I.getType());
    if (TM.Options.AllowFPOpFusion != FPOpFusion::Strict &&
        TLI.isFMAFasterThanFMulAndFAdd(VT)) {
      setValue(&I, DAG.getNode(ISD::FMA, sdl,
                               getValue(I.getArgOperand(0)).getValueType(),
                               getValue(I.getArgOperand(0)),
                               getValue(I.getArgOperand(1)),
                               getValue(I.getArgOperand(2))));
    } else {
      // TODO: Intrinsic calls should have fast-math-flags.
      SDValue Mul = DAG.getNode(ISD::FMUL, sdl,
                                getValue(I.getArgOperand(0)).getValueType(),
                                getValue(I.getArgOperand(0)),
                                getValue(I.getArgOperand(1)));
      SDValue Add = DAG.getNode(ISD::FADD, sdl,
                                getValue(I.getArgOperand(0)).getValueType(),
                                Mul,
                                getValue(I.getArgOperand(2)));
      setValue(&I, Add);
    }



> Ok, we also have another usage of Fast Maths flage in reviev https://reviews.llvm.org/D37616.  Can you please file a bugzilla to track suggested potential improvment.

https://bugs.llvm.org/show_bug.cgi?id=34558


https://reviews.llvm.org/D37686