[LegalizeTypes] When promoting the result of EXTRACT_SUBVECTOR, also check if the input needs to be promoted. Use that to determine the element type to extract.

Otherwise we end up creating extract_vector_elts that then each need to have their input promoted. This can lead to truncates needing to be emitted for each of those.

But we already emitted any_extends when we legalized the extract_subvector. So now we have pairs of any_extend+trunc that partially cancel. But depending on how DAGCombiner visits them we can get weird results.

By promoting the input at the same time we can create only a single any_extend or truncate.

There's one regression in the vector-narrow-binop.ll case, but that looks easy to fix with a follow up patch.

llvm-svn: 354647

1 files changed, 7 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index e664e06ccfd..fa0e7b89eef 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -3667,8 +3667,6 @@ SDValue DAGTypeLegalizer::ExpandIntOp_ATOMIC_STORE(SDNode *N) {
 
 
 SDValue DAGTypeLegalizer::PromoteIntRes_EXTRACT_SUBVECTOR(SDNode *N) {
-  SDValue InOp0 = N->getOperand(0);
-  EVT InVT = InOp0.getValueType();
 
   EVT OutVT = N->getValueType(0);
   EVT NOutVT = TLI.getTypeToTransformTo(*DAG.getContext(), OutVT);
@@ -3679,6 +3677,12 @@ SDValue DAGTypeLegalizer::PromoteIntRes_EXTRACT_SUBVECTOR(SDNode *N) {
   SDLoc dl(N);
   SDValue BaseIdx = N->getOperand(1);
 
+  SDValue InOp0 = N->getOperand(0);
+  if (getTypeAction(InOp0.getValueType()) == TargetLowering::TypePromoteInteger)
+    InOp0 = GetPromotedInteger(N->getOperand(0));
+
+  EVT InVT = InOp0.getValueType();
+
   SmallVector<SDValue, 8> Ops;
   Ops.reserve(OutNumElems);
   for (unsigned i = 0; i != OutNumElems; ++i) {
@@ -3689,7 +3693,7 @@ SDValue DAGTypeLegalizer::PromoteIntRes_EXTRACT_SUBVECTOR(SDNode *N) {
     SDValue Ext = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl,
       InVT.getVectorElementType(), N->getOperand(0), Index);
 
-    SDValue Op = DAG.getNode(ISD::ANY_EXTEND, dl, NOutVTElem, Ext);
+    SDValue Op = DAG.getAnyExtOrTrunc(Ext, dl, NOutVTElem);
     // Insert the converted element to the new vector.
     Ops.push_back(Op);
   }