[DAG] combineConcatVectorOfScalars - stop always creating UNDEF nodes. NFC.
Noticed in debug logs - most calls to visitVECTOR_SHUFFLE resulted into wasteful UNDEF node creations, despite almost never being used.
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index c83793d..7009f37 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -23447,9 +23447,7 @@
SDLoc DL(N);
EVT VT = N->getValueType(0);
SmallVector<SDValue, 8> Ops;
-
EVT SVT = EVT::getIntegerVT(*DAG.getContext(), OpVT.getSizeInBits());
- SDValue ScalarUndef = DAG.getNode(ISD::UNDEF, DL, SVT);
// Keep track of what we encounter.
bool AnyInteger = false;
@@ -23459,7 +23457,7 @@
!Op.getOperand(0).getValueType().isVector())
Ops.push_back(Op.getOperand(0));
else if (ISD::UNDEF == Op.getOpcode())
- Ops.push_back(ScalarUndef);
+ Ops.push_back(DAG.getNode(ISD::UNDEF, DL, SVT));
else
return SDValue();
@@ -23479,13 +23477,12 @@
// Replace UNDEFs by another scalar UNDEF node, of the final desired type.
if (AnyFP) {
SVT = EVT::getFloatingPointVT(OpVT.getSizeInBits());
- ScalarUndef = DAG.getNode(ISD::UNDEF, DL, SVT);
if (AnyInteger) {
for (SDValue &Op : Ops) {
if (Op.getValueType() == SVT)
continue;
if (Op.isUndef())
- Op = ScalarUndef;
+ Op = DAG.getNode(ISD::UNDEF, DL, SVT);
else
Op = DAG.getBitcast(SVT, Op);
}
