[PATCH] D26518: [AArch64] Compute the Newton series for reciprocals natively

[Sanjay Patel via llvm-commits]

spatel added inline comments.


================
Comment at: llvm/lib/Target/AArch64/AArch64ISelLowering.cpp:4658
                                        DAG, ExtraSteps)) {
-      UseOneConst = true;
+      SDLoc DL(Operand);
+      EVT VT = Operand.getValueType();
----------------
jmolloy wrote:
> This seems a bit of a hack. Can we at least get a comment saying this is working around the model somehow?
> 
> Can Sanjay comment on how the model was meant to be used where targets have native step support?
There might be a better API, but this is more or less what I imagined if you want to disable the generic refinement:
  /// A target may choose to implement its own refinement within this function.
  /// If that's true, then return '0' as the number of RefinementSteps to avoid
  /// any further refinement of the estimate.



Repository:
  rL LLVM

https://reviews.llvm.org/D26518