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-rw-r--r--lib/CodeGen/SelectionDAG/DAGCombiner.cpp35
1 files changed, 25 insertions, 10 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index c54dffb..0766849 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9254,19 +9254,34 @@ static SDValue partitionShuffleOfConcats(SDNode *N, SelectionDAG &DAG) {
for (unsigned I = 0; I != NumConcats; ++I) {
// Make sure we're dealing with a copy.
unsigned Begin = I * NumElemsPerConcat;
- if (SVN->getMaskElt(Begin) % NumElemsPerConcat != 0)
- return SDValue();
+ bool AllUndef = true, NoUndef = true;
+ for (unsigned J = Begin; J != Begin + NumElemsPerConcat; ++J) {
+ if (SVN->getMaskElt(J) >= 0)
+ AllUndef = false;
+ else
+ NoUndef = false;
+ }
- for (unsigned J = 1; J != NumElemsPerConcat; ++J) {
- if (SVN->getMaskElt(Begin + J - 1) + 1 != SVN->getMaskElt(Begin + J))
+ if (NoUndef) {
+ unsigned Begin = I * NumElemsPerConcat;
+ if (SVN->getMaskElt(Begin) % NumElemsPerConcat != 0)
return SDValue();
- }
- unsigned FirstElt = SVN->getMaskElt(Begin) / NumElemsPerConcat;
- if (FirstElt < N0.getNumOperands())
- Ops.push_back(N0.getOperand(FirstElt));
- else
- Ops.push_back(N1.getOperand(FirstElt - N0.getNumOperands()));
+ for (unsigned J = 1; J != NumElemsPerConcat; ++J)
+ if (SVN->getMaskElt(Begin + J - 1) + 1 != SVN->getMaskElt(Begin + J))
+ return SDValue();
+
+ unsigned FirstElt = SVN->getMaskElt(Begin) / NumElemsPerConcat;
+ if (FirstElt < N0.getNumOperands())
+ Ops.push_back(N0.getOperand(FirstElt));
+ else
+ Ops.push_back(N1.getOperand(FirstElt - N0.getNumOperands()));
+
+ } else if (AllUndef) {
+ Ops.push_back(DAG.getUNDEF(N0.getOperand(0).getValueType()));
+ } else { // Mixed with general masks and undefs, can't do optimization.
+ return SDValue();
+ }
}
return DAG.getNode(ISD::CONCAT_VECTORS, N->getDebugLoc(), VT, Ops.data(),