[LegalizeVectorTypes] When unrolling in WidenVecRes_Convert, make sure we use the original vector element count. Not min of the widened result type and the possibly widened input type.

If the input type is widened as well, but we still were forced to unroll, we shouldn't be considering the widened input element count. We should only create as many scalar operations as the original type called for.

This will be important for an upcoming patch.

llvm-svn: 344403

1 files changed, 6 insertions, 12 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index 1b07358561a..6bee966a327 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -2809,11 +2809,8 @@ SDValue DAGTypeLegalizer::WidenVecRes_Convert(SDNode *N) {
     if (WidenNumElts % InVTNumElts == 0) {
       // Widen the input and call convert on the widened input vector.
       unsigned NumConcat = WidenNumElts/InVTNumElts;
-      SmallVector<SDValue, 16> Ops(NumConcat);
+      SmallVector<SDValue, 16> Ops(NumConcat, DAG.getUNDEF(InVT));
       Ops[0] = InOp;
-      SDValue UndefVal = DAG.getUNDEF(InVT);
-      for (unsigned i = 1; i != NumConcat; ++i)
-        Ops[i] = UndefVal;
       SDValue InVec = DAG.getNode(ISD::CONCAT_VECTORS, DL, InWidenVT, Ops);
       if (N->getNumOperands() == 1)
         return DAG.getNode(Opcode, DL, WidenVT, InVec);
@@ -2832,11 +2829,12 @@ SDValue DAGTypeLegalizer::WidenVecRes_Convert(SDNode *N) {
   }
 
   // Otherwise unroll into some nasty scalar code and rebuild the vector.
-  SmallVector<SDValue, 16> Ops(WidenNumElts);
   EVT EltVT = WidenVT.getVectorElementType();
-  unsigned MinElts = std::min(InVTNumElts, WidenNumElts);
-  unsigned i;
-  for (i=0; i < MinElts; ++i) {
+  SmallVector<SDValue, 16> Ops(WidenNumElts, DAG.getUNDEF(EltVT));
+  // Use the original element count so we don't do more scalar opts than
+  // necessary.
+  unsigned MinElts = N->getValueType(0).getVectorNumElements();
+  for (unsigned i=0; i < MinElts; ++i) {
     SDValue Val = DAG.getNode(
         ISD::EXTRACT_VECTOR_ELT, DL, InEltVT, InOp,
         DAG.getConstant(i, DL, TLI.getVectorIdxTy(DAG.getDataLayout())));
@@ -2846,10 +2844,6 @@ SDValue DAGTypeLegalizer::WidenVecRes_Convert(SDNode *N) {
       Ops[i] = DAG.getNode(Opcode, DL, EltVT, Val, N->getOperand(1), Flags);
   }
 
-  SDValue UndefVal = DAG.getUNDEF(EltVT);
-  for (; i < WidenNumElts; ++i)
-    Ops[i] = UndefVal;
-
   return DAG.getBuildVector(WidenVT, DL, Ops);
 }