1 files changed, 44 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index d7d7b8b7191..65b738151e6 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -8918,6 +8918,50 @@ SDValue SelectionDAG::UnrollVectorOp(SDNode *N, unsigned ResNE) {
   return getBuildVector(VecVT, dl, Scalars);
 }
 
+std::pair<SDValue, SDValue> SelectionDAG::UnrollVectorOverflowOp(
+    SDNode *N, unsigned ResNE) {
+  unsigned Opcode = N->getOpcode();
+  assert((Opcode == ISD::UADDO || Opcode == ISD::SADDO ||
+          Opcode == ISD::USUBO || Opcode == ISD::SSUBO ||
+          Opcode == ISD::UMULO || Opcode == ISD::SMULO) &&
+         "Expected an overflow opcode");
+
+  EVT ResVT = N->getValueType(0);
+  EVT OvVT = N->getValueType(1);
+  EVT ResEltVT = ResVT.getVectorElementType();
+  EVT OvEltVT = OvVT.getVectorElementType();
+  SDLoc dl(N);
+
+  // If ResNE is 0, fully unroll the vector op.
+  unsigned NE = ResVT.getVectorNumElements();
+  if (ResNE == 0)
+    ResNE = NE;
+  else if (NE > ResNE)
+    NE = ResNE;
+
+  SmallVector<SDValue, 8> LHSScalars;
+  SmallVector<SDValue, 8> RHSScalars;
+  ExtractVectorElements(N->getOperand(0), LHSScalars, 0, NE);
+  ExtractVectorElements(N->getOperand(1), RHSScalars, 0, NE);
+
+  SDVTList VTs = getVTList(ResEltVT, OvEltVT);
+  SmallVector<SDValue, 8> ResScalars;
+  SmallVector<SDValue, 8> OvScalars;
+  for (unsigned i = 0; i < NE; ++i) {
+    SDValue Res = getNode(Opcode, dl, VTs, LHSScalars[i], RHSScalars[i]);
+    ResScalars.push_back(Res);
+    OvScalars.push_back(SDValue(Res.getNode(), 1));
+  }
+
+  ResScalars.append(ResNE - NE, getUNDEF(ResEltVT));
+  OvScalars.append(ResNE - NE, getUNDEF(OvEltVT));
+
+  EVT NewResVT = EVT::getVectorVT(*getContext(), ResEltVT, ResNE);
+  EVT NewOvVT = EVT::getVectorVT(*getContext(), OvEltVT, ResNE);
+  return std::make_pair(getBuildVector(NewResVT, dl, ResScalars),
+                        getBuildVector(NewOvVT, dl, OvScalars));
+}
+
 bool SelectionDAG::areNonVolatileConsecutiveLoads(LoadSDNode *LD,
                                                   LoadSDNode *Base,
                                                   unsigned Bytes,