[DAG Combiner] Fix the native computation of the Newton series for reciprocals

The generic infrastructure to compute the Newton series for reciprocal and
reciprocal square root was conceived to allow a target to compute the series
itself.  However, the original code did not properly consider this condition
if returned by a target.  This patch addresses the issues to allow a target
to compute the series on its own.

Differential revision: https://reviews.llvm.org/D22975

llvm-svn: 286523

1 files changed, 5 insertions, 4 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
index 5a871489acd..a4a5de126df 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -2978,10 +2978,11 @@ const char* AMDGPUTargetLowering::getTargetNodeName(unsigned Opcode) const {
   return nullptr;
 }
 
-SDValue AMDGPUTargetLowering::getRsqrtEstimate(SDValue Operand,
-                                               SelectionDAG &DAG, int Enabled,
-                                               int &RefinementSteps,
-                                               bool &UseOneConstNR) const {
+SDValue AMDGPUTargetLowering::getSqrtEstimate(SDValue Operand,
+                                              SelectionDAG &DAG, int Enabled,
+                                              int &RefinementSteps,
+                                              bool &UseOneConstNR,
+                                              bool Reciprocal) const {
   EVT VT = Operand.getValueType();
 
   if (VT == MVT::f32) {