/// The RefinementSteps output is the number of Newton-Raphson refinement
/// iterations required to generate a sufficient (though not necessarily
/// IEEE-754 compliant) estimate for the value type.
/// The RefinementSteps output is the number of Newton-Raphson refinement
/// iterations required to generate a sufficient (though not necessarily
/// IEEE-754 compliant) estimate for the value type.
/// 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.
/// An empty SDValue return means no estimate sequence can be created.
virtual SDValue getRsqrtEstimate(SDValue Operand,
DAGCombinerInfo &DCI,
/// 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.
/// An empty SDValue return means no estimate sequence can be created.
virtual SDValue getRsqrtEstimate(SDValue Operand,
DAGCombinerInfo &DCI,