[SelectionDAG] Legalize vaargs that require vector splitting

This adds vector splitting for vaarg instructions during type legalization

Committed on behalf of @luke (Luke Lau)

Differential Revision: https://reviews.llvm.org/D60762

llvm-svn: 363671

2 files changed, 24 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index 8beaf145e0f..1d489b1b3a3 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -767,6 +767,7 @@ private:
   void SplitVecRes_SETCC(SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitVecRes_VECTOR_SHUFFLE(ShuffleVectorSDNode *N, SDValue &Lo,
                                   SDValue &Hi);
+  void SplitVecRes_VAARG(SDNode *N, SDValue &Lo, SDValue &Hi);
 
   // Vector Operand Splitting: <128 x ty> -> 2 x <64 x ty>.
   bool SplitVectorOperand(SDNode *N, unsigned OpNo);
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index 072f15b1f4c..5438404d9fc 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -849,6 +849,9 @@ void DAGTypeLegalizer::SplitVectorResult(SDNode *N, unsigned ResNo) {
   case ISD::VECTOR_SHUFFLE:
     SplitVecRes_VECTOR_SHUFFLE(cast<ShuffleVectorSDNode>(N), Lo, Hi);
     break;
+  case ISD::VAARG:
+    SplitVecRes_VAARG(N, Lo, Hi);
+    break;
 
   case ISD::ANY_EXTEND_VECTOR_INREG:
   case ISD::SIGN_EXTEND_VECTOR_INREG:
@@ -1899,6 +1902,26 @@ void DAGTypeLegalizer::SplitVecRes_VECTOR_SHUFFLE(ShuffleVectorSDNode *N,
   }
 }
 
+void DAGTypeLegalizer::SplitVecRes_VAARG(SDNode *N, SDValue &Lo, SDValue &Hi) {
+  EVT OVT = N->getValueType(0);
+  EVT NVT = OVT.getHalfNumVectorElementsVT(*DAG.getContext());
+  SDValue Chain = N->getOperand(0);
+  SDValue Ptr = N->getOperand(1);
+  SDValue SV = N->getOperand(2);
+  SDLoc dl(N);
+
+  const unsigned Alignment = DAG.getDataLayout().getABITypeAlignment(
+      NVT.getTypeForEVT(*DAG.getContext()));
+
+  Lo = DAG.getVAArg(NVT, dl, Chain, Ptr, SV, Alignment);
+  Hi = DAG.getVAArg(NVT, dl, Lo.getValue(1), Ptr, SV, Alignment);
+  Chain = Hi.getValue(1);
+
+  // Modified the chain - switch anything that used the old chain to use
+  // the new one.
+  ReplaceValueWith(SDValue(N, 1), Chain);
+}
+
 
 //===----------------------------------------------------------------------===//
 //  Operand Vector Splitting