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path: root/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
-rw-r--r--lib/CodeGen/SelectionDAG/DAGCombiner.cpp19
1 files changed, 17 insertions, 2 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 6e4a772a89d..4ac6d1b5163 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -8610,8 +8610,8 @@ SDValue DAGCombiner::visitEXTRACT_SUBVECTOR(SDNode* N) {
return SDValue();
// Only handle cases where both indexes are constants with the same type.
- ConstantSDNode *InsIdx = dyn_cast<ConstantSDNode>(N->getOperand(1));
- ConstantSDNode *ExtIdx = dyn_cast<ConstantSDNode>(V->getOperand(2));
+ ConstantSDNode *ExtIdx = dyn_cast<ConstantSDNode>(N->getOperand(1));
+ ConstantSDNode *InsIdx = dyn_cast<ConstantSDNode>(V->getOperand(2));
if (InsIdx && ExtIdx &&
InsIdx->getValueType(0).getSizeInBits() <= 64 &&
@@ -8628,6 +8628,21 @@ SDValue DAGCombiner::visitEXTRACT_SUBVECTOR(SDNode* N) {
}
}
+ if (V->getOpcode() == ISD::CONCAT_VECTORS) {
+ // Combine:
+ // (extract_subvec (concat V1, V2, ...), i)
+ // Into:
+ // Vi if possible
+ for (unsigned i = 0, e = V->getNumOperands(); i != e; ++i)
+ if (V->getOperand(i).getValueType() != NVT)
+ return SDValue();
+ unsigned Idx = dyn_cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
+ unsigned NumElems = NVT.getVectorNumElements();
+ assert((Idx % NumElems) == 0 &&
+ "IDX in concat is not a multiple of the result vector length.");
+ return V->getOperand(Idx / NumElems);
+ }
+
return SDValue();
}